Processor for a Vehicle

ABSTRACT

A processor for a vehicle includes a vehicle yaw moment instruction calculator, and a mode under which yaw moment of the vehicle is controlled. If the vehicle yaw moment instruction value generates the driving forces or the driving torques, the driving forces or driving torques are different between the left and right wheels. If the vehicle yaw moment instruction value generates the braking forces or the braking torques, the braking forces or the braking torques are different between the left and right wheels. The mode operates at least in transit region between daily region and limit region.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.15/042,417, filed Feb. 12, 2016, which is a continuation of U.S.application Ser. No. 14/432,270, filed Mar. 30, 2015, which is aNational Stage of PCT International Application No. PCT/JP2013/075402,filed Sep. 20, 2013, which claims priority from Japanese PatentApplication No. 2012-219017, filed on Oct. 1, 2012, the disclosures ofwhich are expressly incorporated by reference herein.

TECHNICAL FIELD

The present invention relates to a motion controlling apparatus for avehicle which uses a braking force and a driving force.

BACKGROUND ART

In the field of automobiles, in order to implement improvement inenvironmental friendliness, safety and amenity, development not only ofa vehicle controlling system such as an antiskid brake system(Electronic Stability Control: hereinafter referred to as ESC) forpreventing spinning, off the track and so forth during turning but alsoof a vehicle controlling system which uses an intelligent transportationsystem (Intelligent Transport System: hereinafter referred to as ITS)such as a vehicle distance control (Adaptive Cruise Control: hereinafterreferred to as ACC), a lane departure prevention system or pre-crashsafety is being accelerated.

The ESC is vehicle motion control based on the concept of DirectYaw-moment Control (DYC) (refer to Non-Patent Document 1).

This DYC is a technique for controlling the yawing moment for directlypromoting or restoring a yawing motion, which is rotation around a Zaxis of a vehicle, by providing a difference in braking forces ordriving forces between the left and right wheels in order to improve thedrivability and stability of the vehicle as described in Non-PatentDocument 1.

Also a method is available by which acceleration or deceleration isperformed automatically in conjunction with a lateral motion caused by asteering operation to give rise to a load movement between the frontwheels and the rear wheels thereby to achieve improvement in drivabilityand stability of the vehicle (refer to Non-Patent Document 2).

The acceleration/deceleration instruction value for performingacceleration/deceleration automatically (target longitudinalacceleration G_(xc)) is such as represented by the Formula 1 givenbelow.

$\begin{matrix}{G_{xc} = {{{{- {{sgn}\left( {G_{y} \cdot {\overset{.}{G}}_{y}} \right)}}\frac{C_{xy}}{1 + {Ts}}{{\overset{.}{G}}_{y}}} + {G_{x\_ DC}\mspace{14mu} \overset{.}{G}y}} = G_{y\_ dot}}} & \left\lbrack {{Formula}\mspace{14mu} 1} \right\rbrack\end{matrix}$

This formula indicates a simple control strategy that basically a valueobtained by multiplying the lateral jerk G_(y) _(_) _(dot) by a gainC_(xy) to apply a primary delay is used as a forward/rearward orlongitudinal acceleration/deceleration instruction.

It is to be noted that G_(y): vehicle lateral acceleration, G_(y) _(_)_(dot): vehicle lateral jerk, C_(xy): gain, T: primary delay timeconstant, s: Laplace operator, and G_(x) _(_) _(DC): offset.

By this, part of a cooperation control strategy of lateral andforward/backward or longitudinal motions of an expert driver can besimulated, and improvement in drivability and stability of the vehiclecan be implemented.

Where such control as just described is performed, a compositeacceleration (represented by G) of the longitudinal acceleration and thelateral acceleration is vectorized (Vectoring) such that it exhibits acurved transition as time passes on a diagram wherein the axis ofabscissa is the longitudinal acceleration of the vehicle and the axis ofordinate is the lateral acceleration of the vehicle. Therefore, thecontrol is called “G-Vectoring control”.

In this G-Vectoring control, the deceleration of the vehicle iscontrolled in response to the lateral jerk. On the other hand, the ESCcontrols the yaw moment of the vehicle in response to a lateral slip ofthe vehicle. Roughly speaking, the G-Vectoring control controls the sumof braking forces by the tires among the four wheels, and the ESCperforms control of the difference in braking forces between each twoleft and right wheels. From such a relationship as just described, inPatent Document 1, a motion controlling apparatus for a vehicle isdisclosed which is characterized in that the motion controllingapparatus for a vehicle has a first mode in which substantially equalbraking or driving forces are generated by the left and right wheelsfrom among four wheels based on an acceleration/deceleration controllinginstruction linked to a lateral motion and a second mode in whichdifferent braking or driving forces are generated by the left and rightwheels from among the four wheels based on a yaw moment controllinginstruction calculated from lateral slip information of the vehicle.When the yaw moment instruction value is low, the motion controllingapparatus for a vehicle operates in the first mode, and when the yawmoment instruction value is high, the motion controlling apparatus for avehicle operates in the second mode.

PRIOR ART DOCUMENTS Patent Document

-   Patent Document 1: JP-2011-73534-A

Non-Patent Document

-   Non-Patent Document 1: Shibahata, Y; Tomari, T; and Kita, T.;    “SH-AWD: Direct Yaw Control (DYC), 15. Aachener Kolloquium Fahrzeug-    and Motorentechnik, p. 1627, 1640, 1641, 2006-   Non-Patent Document 2: M. Yamakado, M. Abe: Improvement in vehicle    agility and stability by G-Vectoring control, Vehicle System    Dynamics Vol. 48, Supplement, 2010, 231-254

SUMMARY OF THE INVENTION Problem to be Solved by the Invention

The ESC is a method of adjusting the driving forces for the wheelsseparately between the left and right wheels to generate a yawingmovement and performing feedback control so that an ideal motioncalculated on a vehicle motion model and an actual motion may approacheach other. Since the yaw moment required for the control varies everymoment on the basis of the motion state of the vehicle, in order toimplement the yaw moment, roughly speaking, the following tworequirements are applicable.

(1) Insurance of the Calculation Accuracy of an Ideal Motion State byHigh Accuracy and High Speed Calculation of a Vehicle Motion Model,Measurement/Estimation of a Vehicle Motion State, Calculation ofAccurate Lateral Slip Information Thereby, and Calculation-Control of anAccurate Slip Rate

To this end, a controller for exclusive use in an ESC unit is requiredwhose installation in various environments which are different incommunication speed such as a Control Area Network (CAN) and wherein acontrol state quantity itself (slip rate, a hydraulic pressureinstruction or the like) is not influenced by communication with a CANsignal.

(2) Optimization of a Control Intervention Threshold Value for EarlyActuation Prevention

Originally, since the ESC applies different braking forces to the leftand right wheels of the vehicle, when the driver notices operation ofthe ESC, the driver has such a feeling that ordinary braking fails onone side. Further, in the conventional ESC, since a plunger pump havinga small number of cylinders is used or the hydraulic pressureaccumulated in an accumulator is controlled by an ON/OFF valve, relativelarge operating sound and vibration are generated. Therefore, it isnecessary to tune the ESC so that the ESC is actuated only in a reallynecessary scene. To this end, it is necessary to use a rather highcontrol intervention threshold value so that the control is performedafter the vehicle enters an unstable state with certainty.

However, the G-Vectoring control (hereinafter referred to as GVC) isopen loop control where basically an acceleration/deceleration whichincreases in proportion to a lateral jerk of the vehicle is used as acontrol instruction, and therefore the control calculation load is low.Braking on occasions when deceleration control is performed isfour-wheel same pressure control which is same as service braking whichis normally handled by the driver. It has been reported that, even ifsuch control is performed, the driver does not have an sense ofuncomfortableness, and furthermore, high driving comfort since rollingand pitching of the vehicle cooperatively operate. This cooperativeoperation is because part of a cooperation control strategy of lateraland longitudinal motions of an expert driver is simulated. Further,since it is only necessary to perform deceleration control of the speedsimilar to that of the driver, it is possible to implement the controlby sending a control instruction to a brake controller using an ordinaryCAN signal. However, since the GVC involves frequent actuations fromwithin a normal region, an actuator (smart actuator) for deceleration isrequired which is high in Noise, Vibration, and Harshness (NVH)performance in which no operating sound and no vibration are generatedand which is high in durability.

Requirements for each of the ESC and the GVC and requirements for Hybridcontrol of a combination of them are depicted in FIG. 4. As describedhereinabove, although the hybrid control of the ESC and the GVC ishighest in exercise performance, in order for the hybrid control tosatisfy the requirements for the ESC side, it is necessary toincorporate hybrid control software for the ESC and the GVC in acontroller for exclusive use in an ESC unit of premium specificationswhich is superior in NVH performance. Further, by varying, for example,the threshold value on the ESC side to perform “tuning”, it is alsopossible to smoothen cooperation between the GVC and the ESC. Inparticular, it is further possible to adopt a method that, by reducingthe intervention threshold value for oversteer correction of the ESC, animprovement effect of Agility implemented by the GVC is made most of inthe maximum (force the improvement effect to that in the proximity ofthe neutral steer) thereby to cope with any chance of spinning by theESC.

Realistically, it is impossible except an ESC supplier to incorporatehybrid control software for the ESC and the GVC into a controller forexclusive use in an ESC unit. To provide the technology to a greaternumber of drivers, it is necessary to cope with a greater number ofimplementation forms. FIG. 5 depicts a comparison table indicating intowhich controller of hardware a GVC logic is to be incorporated (detailof control other than the GVC is described as conventional control). Forexample, No. 2 of FIG. 5 indicates a configuration that the GVC isimplemented using an electro-hydraulic type brake actuator as a smartactuator and the lateral slip prevention effect is implemented byordinary general-purpose ESC. Further, No. 5 indicates a configurationthat regenerative braking forces in an electric car is used for the GVCand the lateral slip prevention effect is implemented by ordinarygeneral-purpose ESC. Further, Nos. 1, 3, 4 and 6 indicate aconfiguration that, although premium ESC which exhibits a high NVHperformance is used, except No. 1, a GVC logic is incorporated on theouter side of an ESC controller for which high speed calculation isrequired and ESC of premium specifications is externally controlled by aCAN signal.

To implement the modes other than No. 1, transit to slip control or yawcontrol on a low μ road is a problem. Naturally, since slip controlrepresented by an ABS (Anti-lock Braking System) or the like or yawcontrol by the ESC operates even by itself, it is possible to ensureminimum stability. However, to achieve control proximate to seamlesscontrol as can be implemented by Hybrid control, it is necessary toconstruct not only integrated control of the GVC and the ESC but alsonew integrated control in which yaw moment control for transit isadditionally integrated.

It is an object of the present invention to provide a motion controllingapparatus for a vehicle which can achieve improvement in drivability,stability and driving comfort.

Means for Solving the Problem

To achieve the object described above, A motion controlling apparatusfor a vehicle, comprising:

a control unit for controlling independently driving forces or a drivingtorques and/or braking forces or braking torques of wheels of a vehicle;

a vehicle acceleration/deceleration instruction calculator forcalculating a vehicle acceleration/deceleration instruction value on thebasis of a lateral jerk of the vehicle;

a first vehicle yaw moment instruction calculator for calculating afirst vehicle yaw moment instruction value on the basis of the lateraljerk of the vehicle; and

a second vehicle yaw moment instruction calculator for calculating asecond vehicle yaw moment instruction value on the basis of lateral slipinformation of the vehicle,

wherein the motion controlling apparatus further includes:

a first mode under which acceleration/deceleration of the vehicle iscontrolled on the basis of the vehicle acceleration/decelerationinstruction value that generates driving forces or driving torquesand/or braking forces or braking torques of four wheels of the vehicle,the driving forces or driving torques for left wheels and that for rightwheels being substantially equal to each other;

a second mode under which yaw moment of the vehicle is controlled on thebasis of the first vehicle yaw moment instruction value that generatesdriving forces or driving torques and/or braking forces or brakingtorques of four wheels of the vehicle, the driving forces or drivingtorques for left wheels and that for right wheels being different fromeach other; and

a third mode under which yaw moment of the vehicle is controlled on thebasis of the second vehicle yaw moment instruction value that generatesdriving forces or driving torques and/or braking forces or brakingtorques of four wheels of the vehicle, the driving forces or drivingtorques for left wheels and that for right wheels being different fromeach other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram depicting a manner of a G-Vectoring control vehicleafter it approaches a left corner until it leaves the left corner.

FIG. 2 is a diagram depicting a hybrid control configuration for DYC(ESC) and GVC.

FIG. 3 is a diagram depicting operation situations only of ESC and ofhybrid control at a time of lane change.

FIG. 4 is a table indicating requirements for ESC, GVC and hybridcontrol.

FIG. 5 is a comparison table indicating in which controller a GVC logicis to be incorporated.

FIG. 6 is a diagram illustrating a relationship of ESC, Moment+, GVC andhybrid+ control.

FIG. 7 is a diagram depicting an operation range and timing of Moment+control.

FIG. 8 is a diagram depicting a basic policy of a moment controlstrategy.

FIG. 9 is a diagram depicting a basic behavior of the moment controlstrategy.

FIG. 10 is a diagram depicting a jerk at a time of behavior change.

FIG. 11 is a diagram depicting jerk sensor measurement values at a timeof vehicle spinning.

FIG. 12 is a diagram depicting a mode of a lateral slip angle and a yawrate at a time of vehicle spinning.

FIG. 13 is a diagram illustrating a relationship between a statequantity and a control amount (example of OS control).

FIG. 14 is a diagram depicting time series data of a lateral jerk and acontrol amount (OS control).

FIG. 15 is a diagram depicting comparison between a model estimationlateral jerk value and a measurement value.

FIG. 16 is a diagram illustrating a relationship between modelestimation and a measurement value (actual measurement example).

FIG. 17A-17D is a diagram depicting a mechanism for improvingdrivability and stability by braking and driving control.

FIG. 18 is a diagram depicting operation states of three modes of thepresent invention.

FIGS. 19A and 19B is a diagram depicting decoupling of yaw momentcontrol and acceleration/deceleration control of the present invention.

FIG. 20 is a diagram depicting a general configuration of a firstworking example of a motion controlling apparatus for a vehicleaccording to the present invention.

FIG. 21 is a diagram depicting estimation of a vehicle lateralacceleration and jerk for which a vehicle model is used.

FIG. 22 is a diagram depicting vehicle lateral acceleration, jerk andG-Vectoring instruction outputs for which a combined sensor is used.

FIG. 23 is a diagram depicting a concept of mutual complement of anestimation signal and a measurement signal.

FIG. 24 is a diagram depicting a control logic configuration of themotion controlling apparatus for a vehicle according to the presentinvention.

FIG. 25 is a diagram depicting a force and an acceleration applied to avehicle and a yawing motion.

FIG. 26 is a diagram depicting braking and driving force distribution inthree mode operation states of the present invention.

FIG. 27 is a diagram depicting a control configuration of a secondworking example of the motion controlling apparatus for a vehicleaccording to the present invention.

FIG. 28 is a diagram depicting a controller configuration of the secondworking example of the motion controlling apparatus for a vehicleaccording to the present invention.

FIG. 29 is a diagram depicting a vehicle configuration of the secondworking example of the motion controlling apparatus for a vehicleaccording to the present invention.

FIGS. 30A-30C are diagrams depicting a form of a test course for theverification of an effect of the present invention.

FIG. 31 is a table indicating control combinations (2̂3) for theverification of an effect of the present invention.

FIG. 32 is a table indicating results of an L turn test for a vehicle“equivalent to vehicle with Hybrid+ control” of the present inventionand another vehicle “equivalent to vehicle with normal ESC.”

FIG. 33 is a table indicating results of an L turn test for GVC off anda vehicle “equivalent to vehicle with different controller hybridcontrol.”

FIG. 34 is a table indicating results of an L turn test for a GVC & M+vehicle and a vehicle only with GVC.

FIG. 35 is a table indicating result of an L turn test for a vehicleonly with M+ and a vehicle without control.

FIG. 36 is a table indicating results of lane change test for a vehicle“equivalent to vehicle with Hybrid+ control” of the present inventionand another vehicle “equivalent to vehicle with normal ESC.”

FIG. 37 is a table indicating results of a handling road traveling testfor a vehicle “equivalent to vehicle with Hybrid+ control and anothervehicle “equivalent to vehicle with normal ESC.”

FIG. 38 is a table indicating results of a handling road test (steeringstability/feeling evaluation).

FIG. 39 is a table indicating an embodiment which can be achieved by thepresent invention.

MODES FOR CARRYING OUT THE INVENTION

The motion controlling apparatus for a vehicle of the present inventionhas the following configuration as an overview.

The motion controlling apparatus for a vehicle of the present inventionconfigures Hybrid+ control which is a combination of additional momentcontrol (Moment plus; hereinafter referred to as M+) which operates fromwithin a linear region for transit between GVC and ESC with GVC and ESC(DYC) (FIG. 6).

Further, the motion controlling apparatus for a vehicle of the presentinvention is configured such that a deceleration instruction of the GVCand a moment instruction of the M+ are calculated by the same controllerand are sent for a controller for the ESC by communication and then theESC controller integrates the deceleration and the moment so thatcontrol can be performed.

More particularly, the motion controlling apparatus for a vehicleaccording to the present invention has three modes of GVC, ESC and M+.In particular, a motion controlling apparatus for a vehicle which hasmeans capable of controlling driving forces or driving torques and/orbraking forces or braking torques of wheels of the vehicle independentlyof each other includes: vehicle acceleration/deceleration instructioncalculation means for determining a vehicle acceleration/decelerationinstruction value on the basis of a lateral jerk of the vehicle; firstvehicle yaw moment instruction calculation means for determining avehicle yaw moment instruction value based on the lateral jerk of thevehicle; and second vehicle yaw moment instruction calculation means fordetermining a vehicle yaw moment instruction value from lateral slipinformation of the vehicle. The motion controlling apparatus furtherincludes: a first mode (GVC) for generating, on the basis of the vehicleacceleration/deceleration instruction value determined by the vehicleacceleration/deceleration instruction calculation means using thevehicle lateral jerk, substantially equal driving forces or drivingtorques and/or braking forces or braking torques on left and rightwheels from among four wheels of the vehicle to controlacceleration/deceleration of the vehicle; a second mode (M+) forgenerating, on the basis of the vehicle yaw moment instruction valuedetermined by the first vehicle yaw moment instruction calculation meansusing the vehicle lateral jerk, different driving forces or drivingtorques and/or braking forces or braking torques on the left and rightwheels from among the four wheels of the vehicle to control a yaw momentof the vehicle; and a third mode (ESC) for generating, on the basis ofthe vehicle yaw moment instruction value determined by the secondvehicle yaw moment instruction calculation means using the vehiclelateral slip information, different driving forces or driving torquesand/or braking forces or braking torques on the left and right wheelsfrom among the four wheels of the vehicle to control the yaw moment ofthe vehicle.

Further, the motion controlling apparatus for a vehicle is configuredsuch that the first mode includes one or both of: a 1.1th mode (GVC−),applied when a product of the vehicle lateral acceleration and thevehicle lateral jerk is positive, under which deceleration of thevehicle is controlled on the basis of the vehicleacceleration/deceleration instruction value determined by the vehicleacceleration/deceleration instruction calculation means using thelateral jerk of the vehicle; and a 1.2th mode (GVC+), applied when theproduct of the vehicle lateral acceleration and the vehicle lateral jerkis negative, under which acceleration of the vehicle is controlled onthe basis of the vehicle acceleration/deceleration instruction valuedetermined by the vehicle acceleration/deceleration instructioncalculation means using the lateral jerk of the vehicle.

Further, the motion controlling apparatus for a vehicle is configuredsuch that the second mode includes one or both of: a 2.1th mode (M++),applied when the product of the vehicle lateral acceleration and thevehicle lateral jerk is in the positive, under which a yaw moment on theturning promotion side of the vehicle is controlled on the basis of ayaw moment instruction value at a vehicle turning promotion side servingas the first vehicle yaw moment instruction value, the first vehicle yawmoment instruction value being determined by the first vehicle yawmoment instruction calculation means using the lateral jerk of thevehicle; and a 2.2th mode (M+−), applied when the product of the vehiclelateral acceleration and the vehicle lateral jerk is in the negative,under which a yaw moment instruction value on the vehicle stabilizationside of the vehicle is controlled on the basis of a yaw momentinstruction value on the vehicle stabilization side which is the firstvehicle yaw moment instruction value, the first vehicle yaw momentinstruction value being determined by the first vehicle yaw momentinstruction calculation means using the lateral jerk of the vehicle.

Further, the motion controlling apparatus for a vehicle is configuredsuch that the third mode for controlling the yaw moment of the vehicleaccording to the lateral slip information includes both of: a 3.1th mode(ESC−) under which the yaw moment on the stabilization side of thevehicle is controlled on the basis of the yaw moment instruction valueon the vehicle stabilization side determined by the second vehicle yawmoment instruction calculation means using the vehicle lateral slipinformation; and a 3.2th mode (ESC+) under which the yaw moment on theturning promotion side of the vehicle is controlled on the basis of theyaw moment instruction value on the vehicle turning promotion side.

Further, the motion controlling apparatus for a vehicle is configuredsuch that it further includes arbitration means for arbitrating thefirst vehicle yaw moment instruction value determined by the firstvehicle yaw moment instruction calculation means and the second vehicleyaw moment instruction value determined by the second vehicle yaw momentinstruction calculation means, and that one of the first vehicle yawmoment instruction value and the second vehicle yaw moment instructionvalue which has a higher absolute value is adopted.

Furthermore, the motion controlling apparatus for a vehicle isconfigured such that at least the vehicle acceleration/decelerationinstruction calculation means and the first vehicle yaw momentinstruction calculation means are provided in the same controller. Thevehicle acceleration/deceleration instruction value and the vehicle yawmoment instruction value are transmitted from the controller bycommunication to means for controlling driving forces or driving torquesand/or braking forces or braking torques to the wheels of the vehicleindependently of each other.

Here, a basic idea of the present invention is described in more detail.

To implement such seamless control as can be implemented by such Hybridcontrol as depicted in FIGS. 2 and 3 in various forms, it is necessaryto construct new integrated control which not only includes integratedcontrol of the GVC and the ESC but also additionally includes yaw momentcontrol for transit. The moment control for transit is represented asMoment+(moment plus) and is hereinafter referred to as M+. FIG. 7 is aschematic diagram depicting an operation range and timing of the M+.

At an upper stage of FIG. 7, a comparison between a target yaw rate,which is based on the steering angle and the vehicle speed, and anactual yaw rate. Here, a situation is assumed in which the ESC operatesbecause the target yaw rate deviates from the actual yaw rate andexceeds an intervention threshold value. The GVC operates by applyingequal braking forces to the left and right wheels for a period of timeafter starting of turning till entering steady turning, namely, within anormal region, and enhances both of the yaw rate gain and the lateralacceleration gain to improve the turning performance. Further, in theHybrid control where both of the GVC and the ESC are incorporated in thesame ESC controller, seamless control in all of the daily, transit andlimit regions can be implemented. On the other hand, in the case of No.4 in FIG. 5 wherein, for example, the ESC manufactured by a company A isadopted and the GVC is incorporated in an Advanced Driver Assist System(ADAS) controller manufactured by another company B, it is difficult toimplement such seamless control as is implemented by the Hybrid control.The ESC does not operate unless the deviation between the target yawrate and the actual yaw rate exceeds an intervention threshold valuedetermined by the company A, and the motion control in the transitregion between the daily region and the limit region becomesdiscontinuous.

Therefore, the M+ is configured such that moment control is started fromwithin the transit region aiming at such effects as given below:

-   -   The yaw rate deviation is reduced from a point before the ESC        becomes operative thereby to reduce the frequency of abrupt        sudden intervention.    -   Even if the ESC starts operation, the ESC control input        amplitude is reduced by intervention from within an early state.    -   In the limit region, a moment instruction value is generated        together with the ESC as occasion demands.

New control wherein the M+ control having such control effects asdescribed above and the GVC are combined is constructed, and the controlcalculation unit is incorporated in a controller other than the ESC.Thus, by sending a control instruction to the ESC, such a variety ofmodes as a mode in which a general-purpose ESC is used independently ofthe maker, another mode in which an electro-hydraulic type brakeactuator is used for the normal region control (No. 2 of FIG. 5) and afurther mode in which regenerative braking of an EV is used (No. 5 ofFIG. 3) can be implemented.

Now, the moment control strategy in the transit state is examined. Inthe transit state, a control strategy which exhibits a vehiclestabilizing effect also in the transit state from the normal state tothe limit state is required. Here, it is intended to derive a basicpolicy and a particular control strategy.

<Basic Policy of the Moment Control Strategy>

As a constraint condition for the control strategy of the M+, thefollowing points of view are involved.

-   -   Wheel speed and lateral slip angle information which is being        calculated at a high speed in the inside of the ESC controller        is not used.    -   A simple control strategy which can be understood intuitively        (the step number for tuning is small).    -   Cooperation with the GVC can be performed readily.

In addition, for control which operates in the transit state, if themoment control strategy has a configuration like a select highconfiguration of control for a daily region+α (region near by a smallamount from the daily region to the limit) and the limit region, then itcan be expected that a seamless control instruction can be obtained.Then, if the control entered the limit region, then transit to the ESCcontrol (select high) is performed (FIG. 8).

When to derive a control strategy for the daily region+α, it wasdetermined to refer to a driving behavior of a driver from the idea of“human-inspired (to mimic a driving behavior of a human being). Further,it was determined to derive a limit region control strategy on the basisof a vehicle behavior immediately before spinning occurs. In thedescription beginning with the next paragraph, control in the dailyregion and control in the limit region are successively examined.

<Derivation of a Control Strategy for the Moment+>

Daily Region+α Control

Although one accelerator pedal and one brake pedal are providednaturally, the driver cannot directly control the braking forces and thedriving forces independently of each other to control the yaw moment.Accordingly, the control strategy for the yaw moment cannot be found outdirectly like the GVC (simulating a driving behavior of a human being).Therefore, a yaw moment generated by load movement based on a voluntaryacceleration/deceleration behavior of the driver when the car iscornering is reconfirmed to achieve derivation of a control algorithm.

The GVC is acceleration/deceleration control associated with a lateralmotion. Meanwhile, if acceleration or deceleration is performed, thenthe vertical load to the tires moves. For example, during deceleration,the vertical load moves from the rear wheels to the front wheels, butduring acceleration, the vertical load moves from the front wheels tothe rear wheels. On the other hand, as well known in the art, thecornering force is load-dependent. Here, where the cornering stiffnessis represented by Ki (i=f, r, f: front, r: rear), when they have afirst-order load dependency (proportional coefficient C₁) on the tirevertical load Wi, the cornering stiffness Ki can be represented by theFormula 2 given below.

K _(i) =C ₁ W _(i)  [Formula 2]

On the other hand, where the height of the center of gravity of thevehicle is represented by h, if the vehicle accelerates or deceleratesby G_(x), the front wheel load W_(f) (to one front wheel) is representedby the Formula 3 given below.

$\begin{matrix}{W_{f} = {\frac{m\; l_{r}g}{2l}\left( {1 - {\frac{h}{l_{r}g}G_{x}}} \right)}} & \left\lbrack {{Formula}\mspace{14mu} 3} \right\rbrack\end{matrix}$

The rear wheel load W_(r) (to one rear wheel) is represented by theFormula 4 given below.

$\begin{matrix}{W_{r} - {\frac{m\; l_{f}g}{2l}\left( {1 + {\frac{h}{l_{f}g}G_{x}}} \right)}} & \left\lbrack {{Formula}\mspace{14mu} 4} \right\rbrack\end{matrix}$

Accordingly, the cornering stiffness K_(f) and K_(r) are represented bythe Formula 5 and the Formula 6 for the front and rear wheels,respectively.

$\begin{matrix}{K_{f} = {{C_{l}W_{f}} = {{C_{l}\frac{m\; l_{r}g}{2l}\left( {1 - {\frac{h}{l_{r}g}G_{x}}} \right)} = {K_{f\; 0}\left( {1 - {\frac{h}{l_{r}g}G_{x}}} \right)}}}} & \left\lbrack {{Formula}\mspace{14mu} 5} \right\rbrack \\{K_{r} = {{C_{l}W_{r}} = {{C_{l}\frac{m\; l_{f}g}{2l}\left( {1 + {\frac{h}{l_{f}g}G_{x}}} \right)} = {K_{r\; 0}\left( {1 + {\frac{h}{l_{f}g}G_{x}}} \right)}}}} & \left\lbrack {{Formula}\mspace{14mu} 6} \right\rbrack\end{matrix}$

Here, if it is assumed that the cornering forces increase in proportionto the lateral slip angle R, then the Formula 7 and the Formula 8 givenbelow are satisfied.

$\begin{matrix}{Y_{f} = {{{- K_{f}}\alpha_{f}} = {{{- K_{f\; 0}}\left\{ {\left( {1 - {\frac{h}{l_{r}g}G_{x}}} \right)\alpha_{f}} \right\}} = {Y_{f\; 0}\left( {1 - {\frac{h}{l_{r}g}G_{x}}} \right)}}}} & \left\lbrack {{Formula}\mspace{14mu} 7} \right\rbrack \\{Y_{r} = {{{- K_{r}}\alpha_{r}} = {{{- K_{r\; 0}}\left\{ {\left( {1 + {\frac{h}{l_{f}g}G_{x}}} \right)\alpha_{r}} \right\}} = {Y_{r\; 0}\left( {1 + {\frac{h}{l_{f\;}g}G_{x}}} \right)}}}} & \left\lbrack {{Formula}\mspace{14mu} 8} \right\rbrack\end{matrix}$

If the relations given above are substituted into an equation of thelateral acceleration and the yaw motion, then the Formula 9 and theFormula 10 given below are obtained.

$\begin{matrix}\begin{matrix}{{mG}_{y} = {{2\left( {Y_{f\; 0} + Y_{r\; 0}} \right)} - {\frac{2\; h}{g}\left( {\frac{Y_{f\; 0}}{l_{r}} - \frac{Y_{r\; 0}}{l_{f}}} \right)G_{x}}}} \\{= {{2\left( {Y_{f\; 0} + Y_{r\; 0}} \right)} - {\frac{h}{{gl}_{f}l_{r}}2\left( {{l_{f}Y_{f\; 0}} - {l_{r}Y_{r\; 0}}} \right)G_{x}}}} \\{= {{mG}_{y\; 0} - {\frac{h}{{gl}_{f}l_{r}}I_{z}{\overset{.}{r}}_{0}G_{x}}}} \\{= {{mG}_{y\; 0} - {\frac{mh}{g}{\overset{.}{r}}_{0}G_{x}}}}\end{matrix} & \left\lbrack {{Formula}\mspace{14mu} 9} \right\rbrack \\\begin{matrix}{{I_{z}\overset{.}{r}} = {2\left( {{l_{f}{Y_{r\; 0}\left( {1 - {\frac{h}{l_{r}g}G_{x}}} \right)}} - {l_{r}{Y_{r\; 0}\left( {1 + {\frac{h}{l_{f}g}G_{x}}} \right)}}} \right)}} \\{= {{2\left( {{l_{f}Y_{f\; 0}} - {l_{r}Y_{r\; 0}}} \right)} - {2\frac{h}{g}\left( {{\frac{l_{f}}{l_{r}}Y_{f\; 0}} + {\frac{l_{r}}{l_{f}}Y_{r\; 0}}} \right)G_{x}}}} \\{{\approx {{I_{z}{\overset{.}{r}}_{0}} - {\frac{mh}{g}G_{y\; 0}G_{x}\mspace{95mu} \bullet \overset{\bullet}{\underset{\bullet}{\times}}\bullet {\overset{.}{r}}_{0}}}} = r_{0{\_ dot}}}\end{matrix} & \left\lbrack {{Formula}\mspace{14mu} 10} \right\rbrack\end{matrix}$

Here, G_(y0) and r₀ _(_) _(dot) are the original lateral accelerationand the original yaw angular velocity when none of acceleration anddeceleration is performed, respectively. If attention is paid to thefinally transformed terms in the Formula 9 and the Formula 10 of theequation of motions, then it can be recognized that, if G_(x) is in thenegative, namely, if the vehicle decelerates, then the lateralacceleration and the yaw motion are strengthened.

In the Formula 10 of the equation of motion, the yaw moment I_(z) ofinertia can be approximately rewritten into the Formula 11 given below.

I _(z) =m·1_(f) ·l _(r)  [Formula 11]

Accordingly, if the Formula 11 is substituted into the Formula 9 and theFormula 10 and resulting formulas are arranged in a matrix form and thenthe GVC control strategy is applied to the formulas, then the Formula 12given below is obtained.

$\begin{matrix}{\begin{pmatrix}{mG}_{y} \\{I_{z}\overset{.}{r}}\end{pmatrix} = {{\begin{pmatrix}F_{y\; 0} \\M_{0}\end{pmatrix} - {\frac{{mhG}_{x}}{g}\begin{pmatrix}0 & 1 \\1 & 0\end{pmatrix}\begin{pmatrix}G_{y\; 0} \\{\overset{.}{r}}_{0}\end{pmatrix}}} = {\begin{pmatrix}F_{y\; 0} \\M_{0}\end{pmatrix} + {\frac{{mhG}_{x\mspace{11mu} {\_ GVC}}}{g}\begin{pmatrix}0 & 1 \\1 & 0\end{pmatrix}\begin{pmatrix}G_{y\; 0} \\{\overset{.}{r}}_{0}\end{pmatrix}}}}} & \left\lbrack {{Formula}\mspace{14mu} 12} \right\rbrack\end{matrix}$

The Formula 12 means that the influence by the GVC acts upon both of theyaw motion and the lateral acceleration. Further, it can be recognizedthat the influence degree on the lateral acceleration is represented bya form of the product of the acceleration or deceleration and the yawmotion while the influence degree on the yaw motion is represented by aform of the product of the acceleration or deceleration and the lateralacceleration, and they influence each other in a cross coupled fashion.In the following, the moment control for stabilization is examined onthe basis of the relationship just described.

In the GVC, an acceleration instruction is issued when the lateral jerkis in the negative when the car is leaving from a corner. However, on atest vehicle on which brake control is emphasized, only a decelerationinstruction of the GVC is used. However, on the acceleration side,control is not performed but is entrusted to the driver (G_(x) _(_)_(DRV)).

Accordingly, at a time of approach to a corner, automatic deceleration(G_(x) _(_) _(GVC)) is performed by the GVC (given by the Formula 13below).

$\begin{matrix}{\begin{pmatrix}{mG}_{y} \\{I_{z}\overset{.}{r}}\end{pmatrix} = {\begin{pmatrix}F_{y\; 0} \\M_{0}\end{pmatrix} + {\frac{{mhG}_{x\mspace{11mu} {\_ GVC}}}{g}\begin{pmatrix}0 & 1 \\1 & 0\end{pmatrix}\begin{pmatrix}G_{y\; 0} \\{\overset{.}{r}}_{0}\end{pmatrix}}}} & \left\lbrack {{Formula}\mspace{14mu} 13} \right\rbrack\end{matrix}$

When a car is leaving a corner, acceleration (G_(x) _(_) _(DRV)) isperformed by the driver (given by the Formula 14).

$\begin{matrix}{\begin{pmatrix}{mG}_{y} \\{I_{z}\overset{.}{r}}\end{pmatrix} = {\begin{pmatrix}F_{y\; 0} \\M_{0}\end{pmatrix} - {\frac{{mhG}_{x\mspace{11mu} {\_ DRV}}}{g}\begin{pmatrix}0 & 1 \\1 & 0\end{pmatrix}\begin{pmatrix}G_{y\; 0} \\{\overset{.}{r}}_{0}\end{pmatrix}}}} & \left\lbrack {{Formula}\mspace{14mu} 14} \right\rbrack\end{matrix}$

Here, it is also considered that not only the driver merely wants toaccelerate the vehicle (increase the speed) but also the driver sets theG_(x) to a positive value in the yaw motion of the Formula 14 to movethe load to the rear wheels by load movement to reduce the yaw momentthereby to make it easy to return to the straightly traveling state.

According to this hypothesis, it is only necessary to apply a moment ina direction in which the yaw motion is stabilized at a timing similar tothat by the driver. Further, the driver confirms that an instruction anda profile on the acceleration side of the GVC have acceleration formssimilar to each other (refer to Non-Patent document 2).

In particular, driver assist control for the daily region+α becomes suchthat, “when an instruction on the acceleration side is issued in theGVC, a moment on the restoration side which reduces the yaw motion maybe applied to the vehicle”. Here, taking an analogy to the GVCinstruction value of the Formula 1 into consideration, when G_(x) _(_)_(DRV)>0, namely, when −sgn(G_(y)·G_(y) _(_) _(dot))>0, the Formula 15given below is obtained.

$\begin{matrix}{M_{+ n} = {{{sgn}\left( {G_{y} \cdot {\overset{.}{G}}_{y}} \right)}\frac{C_{mn}}{1 + {T_{mn}s}}{{\overset{.}{G}}_{y}}}} & \left\lbrack {{Formula}\mspace{14mu} 15} \right\rbrack\end{matrix}$

It is to be noted that C_(mn) is a proportional coefficient, and T_(mn)is a primary delay time constant. This is the basic rule of the dailyregion+α control. Further, if the sgn term and the primary delay areomitted for simplification and the deceleration by the GVC and themoment control by the M+ are described in an integrated form, then theFormula 16 given below is obtained. It is to be noted that C_(mn) is aproportional constant.

$\begin{matrix}\begin{matrix}{\begin{pmatrix}{mG}_{y} \\{I_{z}\overset{.}{r}}\end{pmatrix} = {\begin{pmatrix}F_{y\; 0} \\M_{0}\end{pmatrix} - {\frac{{mhC}_{xy}G_{x\mspace{11mu} {\_ GVC}}}{g}\begin{pmatrix}0 & 1 \\1 & 0\end{pmatrix}\begin{pmatrix}G_{y\; 0} \\{\overset{.}{r}}_{0}\end{pmatrix}} + \begin{pmatrix}0 \\M_{+ n}\end{pmatrix}}} \\{= {\begin{pmatrix}F_{y\; 0} \\M_{0}\end{pmatrix} + {\left\{ {{\frac{{mhC}_{xy}}{g}\begin{pmatrix}0 & 1 \\1 & 0\end{pmatrix}\begin{pmatrix}G_{y\; 0} \\{\overset{.}{r}}_{0}\end{pmatrix}} - \begin{pmatrix}0 \\C_{mn}\end{pmatrix}} \right\} {{\overset{.}{G}}_{y}}}}}\end{matrix} & \left\lbrack {{Formula}\mspace{14mu} 16} \right\rbrack\end{matrix}$

After all, the deceleration and the stabilization moment are applied inresponse to the lateral jerk G_(y) _(_) _(dot). FIG. 9 denotes a diagramof a basic concept of the integrated control.

In the daily region, the correlation between the steering angle input ofthe driver and the vehicle behavior determined by calculation on avehicle motion model is high. Further, the steering angle reflects anintention of the driver against the yawing motion and serves as a signal“whose phase leads” with respect the vehicle behavior to make phasecompensation of the control system possible. Accordingly, when themoment control in the daily region is performed, the lateral jerkestimated using the vehicle motion model may be used for control inaccordance with a GVC instruction similarly as in the case described inPatent Document 1.

(Note: here, a low friction region on a snow-covered road or the like isregarded as an operation range. When the driver operates the acceleratorpedal to issue an acceleration request when the car is in turningleaving on an asphalt road or the like, also the moment control by abrake is cancelled immediately.)

Control in the Limit Region

When the balance in force is lost by some cause, a variation inacceleration, namely, a jerk, is generated (FIG. 10).

FIG. 11 depicts measurement values of a jerk sensor when the side brakeis pulled during turning to place the tire forces of the rear wheelsinto a saturate state thereby to cause a behavior variation (spin) andthen the side brake is loosened. A manner in which, when the side brakeis pulled, the lateral acceleration drops simultaneously and a jerk inthe opposite direction to that of the lateral acceleration is generatedcan be seen from FIG. 11. If the side brake is loosened reversely, thenthe lateral acceleration gradually recovers and a jerk in the directionsame as that of the lateral acceleration is generated. The knowledgeobtained from here is that “the time at which the product of theacceleration and the jerk is in the negative is the time at which thevehicle begins to slip” and “the time at which the product is in thepositive is the time at which the vehicle stops slipping and the motionis returning to the original state”. This is not limited to the lateralmotion, but applies also with regard to the longitudinal direction. Inthis manner, a situation in which the vehicle slips and anothersituation in which the vehicle restores from the slipping can bedetected from the acceleration and the jerk.

Here, a behavior variation including spinning is examined a little moreparticularly. It is assumed that the vehicle is traveling stably in astate in which the angle defined by the direction in which the point ofthe center of gravity of the vehicle advances and the center line of thevehicle in the longitudinal direction, namely, the lateral slip angle β,is almost zero (β_dot=0). The yaw rate at this time is r₀, and thelateral acceleration of the vehicle has, where the vehicle speed isrepresented by V_(o), a relationship of G_(y)=V_(o)×r₀.

Here, if the vehicle starts spinning, then for a period of ΔT, r₀ and β₀become r₀→r₁ (>r₀) and β₀→β₁, and r₁ _(_) _(dot) and β₁ _(_) _(dot)become r₁ _(_) _(dot)=(r₁−r₀)/ΔT>0 and β₁ _(_) _(dot)=β₁/ΔT<0,respectively. Where the yaw moment in the original restoration directionof the vehicle is small and besides control by the DYC or the like isnot performed, if ΔT elapses further, then the lateral slip angleincreases, resulting in occurrence of spinning of the vehicle.

The lateral acceleration can be represented in the following mannerusing the velocity V, the lateral slip angular velocity β_(—dot) and theyaw rate r.

G _(y) =V({dot over (β)}+r) {dot over (β)}=β_(—dot)  [Formula 17]

In the case of spinning, the lateral acceleration drops without fail incomparison with the lateral acceleration in a preceding steady state.This is because the positive increasing amount of r increases thelateral acceleration in the negative direction of β (β₁ _(_) _(dot)<0).Therefore, although the lateral jerk is given by the Formula 18, at atime of spinning, the value of the lateral jerk becomes a negativevalue.

Ġ _(y) =G _(x)({dot over (β)}+r)+V({umlaut over (β)}+{dot over(r)})  [Formula 18]

The event of “the time at which the product of the acceleration and thejerk is in the negative is the time at which the vehicle begins to slip”is satisfied at the spinning.

(Postscript 1: the first term of the Formula 18 is a rotationalcomponent of the jerk and can be regarded also as a centrifugal jerk(≈r·G_(x)))(Postscript 2: as the lateral slip angle increases, since the lateralacceleration which can be measured by the lateral acceleration sensor isa cos β component of the centrifugal force (acting in a direction towardthe center of the turning route), the measurement value itself drops)

Now, if a sufficiently short period of time is considered and it isassumed that the longitudinal acceleration is fixed and also thevelocity is fixed, then the lateral jerk can be considered as given bythe following Formula 19.

$\begin{matrix}{{\overset{.}{G}}_{y} = {{V\left\{ {\left( {\overset{¨}{\beta} + {\frac{G_{x}}{V}\overset{.}{\beta}}} \right) + \left( {\overset{.}{r} + {\frac{G_{x}}{V}r}} \right)} \right\}} = {{A_{1}\overset{¨}{\beta}} + {A_{2}\overset{.}{\beta}} + {A_{1}\overset{.}{r}} + {A_{2}r}}}} & \left\lbrack {{Formula}\mspace{14mu} 19} \right\rbrack\end{matrix}$

The lateral jerk can be regarded as the sum of the lateral slip anglevariation, lateral slip angle, yaw angle acceleration or yaw angularvelocity with a coefficient given by a value represented by the velocityor the ratio between the acceleration and the velocity. Although theratio varies, it has at least a causal relationship with the lateraljerk, and it is considered that, when a lateral jerk is generated, thequantities of them are varying. In the preceding example of spinning, itis considered that the yaw rate and the yaw angular velocity increaseand the lateral slip angle and the lateral slip angular velocityincrease in the negative direction.

FIG. 13 depicts an example of OS control of the ESC. In this logic, atarget moment instruction is determined, on the basis of the deviationbetween the target yaw rate or lateral slip angle estimated using thevehicle model and the measurement yaw rate or the lateral slip angleestimated using an observer and the absolute value of the lateral angle,by addition or select high of the deviation and the absolute value.

The yaw rate and the lateral slip angle deviation are examined. FIG. 14is a diagram depicting them in a generalized form. If the differencebetween the target lateral motion and the actual lateral motion, namely,the lateral motion variation, is extracted and indicated on the timeaxis, then a diagram at the middle stage is obtained. After a point oftime at which the lateral motion variation exceeds an interventionthreshold value therefore, a moment instruction is calculated on thebasis of the values of them.

If the lateral motion deviation in the case where the target lateralmovement is zero is considered, then this is the actual lateral motionitself. It is considered that the time differential value of the lateralmovement deviation at this time can be represented by an actual jerk(lower stage in FIG. 14). Further, where the target lateral movement isa sufficiently slow movement, this can be regarded as an equilibriumpoint and the lateral motion deviation can be regarded as a finedisturbance from the equilibrium point. Since the time differentialvalue at the equilibrium point is zero, it is considered that the timedifferential value of the lateral motion deviation still is a timedifferential value of the actual lateral motion. In the followingdescription, the lateral jerk is regarded as an instruction value forthe moment control.

As described hereinabove, it can be considered that “the time at whichthe product of the acceleration and the jerk is in the negative is thetime at which the vehicle begins to slip” or “the time is the time atwhich the vehicle begins to spin”. At this time, a moment in theopposite direction (restoration direction) to that of spinning may beapplied to the vehicle. If the moment instruction at this time isformulated most directly, then the Formula 20 is obtained.

$\begin{matrix}{M_{z} = \left\{ \begin{matrix}0 & \left( {{{{if}\mspace{14mu} \text{:}} - {{sgn}\left( {G_{y} \cdot {\overset{.}{G}}_{y}} \right)}} \leq 0} \right) \\{{- C_{ml}}{{\overset{.}{G}}_{y}}} & \left( {{{{if}\mspace{14mu} \text{:}} - {{sgn}\left( {G_{y} \cdot {\overset{.}{G}}_{y}} \right)}} > 0} \right)\end{matrix} \right.} & \left\lbrack {{Formula}\mspace{14mu} 20} \right\rbrack\end{matrix}$

It is to be noted that C_(ml) is a proportional constant. This is notcontradictory to that, in regard to the daily region+α described in thepreceding section, “when an instruction on the acceleration side isissued in the GVC, a moment on the restoration side for reducing the yawmotion may be applied to the vehicle”. Accordingly, if the proportionalconstants C_(mn) above and C_(ml) are selected appropriately, thenseamless integrated control from the daily region to the limit regioncan be configured (naturally, also the ESC intervenes on the basis ofthe lateral slip information).

To Make M+ Control Seamless

Also in the GVC control till now, control has been performed using amodel estimation lateral jerk value estimated using a vehicle motionmodel and a measurement value as depicted in FIG. 15 (refer to PatentDocument 3). The jerk information of an early phase by model estimationis effective to achieve, by load movement to the front wheels bydeceleration through starting of the control at an early stage,improvement in responsive feeling to steering. Further, it was confirmedthat, by performing deceleration associated also with a vehicle lateralmotion which occurs late after steering is stopped, although this isprincipally for a low friction road, abrupt ending of the control doesnot occur and sense of continuity is obtained.

It was determined to use a similar technique also when it was tried tomake the M+ control from the daily region to the limit region seamless.FIG. 16 indicates a result of a simulation test on a compacted snowroad. Although actual control was not performed, a steering angle and avehicle behavior when spinning is induced by an L turn and aninstruction value calculated on the basis of the steering angle and thevehicle behavior are indicated. Although the GVC instruction on thedeceleration side was regarded as select high (as viewed in absolutevalue) to construct an instruction value already, at this time, also asregards the instruction value on the acceleration side, it wasdetermined to obtain a moment instruction value (M_(z) _(_) _(GVC))through select high of the instruction value based on the modelestimation (G_(y) _(_) _(dot) Estimated) and the instruction value basedon the measured value (G_(y) _(_) _(dot) Measured). By adopting such aconfiguration as just described, it is possible to obtain a controlstrategy complying with such a “basic policy for a moment controlstrategy” as described hereinabove. Further, although a decelerationinstruction by model estimation appears around 8 seconds, since the GVCand the moment instruction do not interfere with each other, also it ispossible to carry out both controls. At this time, the operation is suchthat the vehicle is decelerated while a moment on the restoration sideis applied.

Integrated Control (Hybrid+ Enhanced Control)

Although the brake control by the ESC is focused above, here, asituation in which four-wheel independent braking and driving control ispossible is considered, and this is referred to as Hybrid+ Enhancedcontrol. Where the four wheels can be braked and driven independently ofone another, the left and right braking/driving sum can be made fixedwhile a moment is generated from a difference between the left and rightwheels in driving-braking. As a result, the moment can be controlledarbitrarily while the acceleration and the deceleration are controlledarbitrarily.

In addition to direct control of the moment by providing a difference inbraking or driving forces between the left and right wheels, the momentcan be controlled, although indirectly, using the difference in lateralforces between the front and rear wheels by load movement between thefront and rear wheels which occurs by acceleration or decelerationduring turning as depicted in FIG. 17C and FIG. 17D. Although, in thebrake control described hereinabove, even if it is tried to control themoment, also a deceleration appears naturally, if also the drivingforces can be controlled, then by applying driving forces equally to allwheels as depicted in FIGS. 17A and 17B, only the moment can becontrolled without involving acceleration or deceleration. In such asituation as just described, the acceleration or deceleration iscontrolled by an acceleration behavior of the driver and the GVC, andthe moment can be controlled by the M+ and the ESC (DYC) on the basis ofthe lateral slip information. Here, if the M+ control is expanded fromthe control only of the stable side of the Formula 20 to turn promotioncontrol when the car is turning in, then this is represented by theFormula 21.

FIG. 17A depicts addition of positive moment by left-right differentialbraking-driving input. FIG. 17B depicts addition of negative moment byleft-right differential braking-driving input. FIG. 17C depicts positivemoment increasing effect utilizing load movement from rear wheels tofront wheels by braking. FIG. 17D depicts negative moment increasingeffect utilizing load movement from rear wheels to front wheels bydriving.

$\begin{matrix}{M_{z +} = {{{sgn}\left( {G_{y} \cdot {\overset{.}{G}}_{y}} \right)}\frac{C_{{mn}\; 1}}{1 + {T_{mn}s}}{{\overset{.}{G}}_{y}}}} & \left\lbrack {{Formula}\mspace{14mu} 21} \right\rbrack\end{matrix}$

However, it is necessary to set the lateral acceleration gain C_(mnl) toan appropriate value over a range from the normal region to the limitregion.

If such a configuration as described above is applied, then such Hybrid+Enhanced control as depicted in FIG. 18 can be implemented. FIG. 18indicates, from above, as follows: a driver steering angle; a lateralacceleration estimation value G_(ye); a lateral acceleration measurementvalue G_(ys); time rates of change G_(ye) _(_) _(dot) and G_(ys) _(_)_(dot) of the values G_(ye) and G_(ys) (estimation and detection arehereinafter described); an acceleration/deceleration instruction valueby the GVC based on the lateral jerk; an acceleration/decelerationinstruction value of the driver estimated from the operation amount ofthe brake/accelerator pedal; a substantial deceleration instruction(G_(xc)) in which arbitration of the acceleration/decelerationinstruction of the driver and the acceleration/deceleration instructionof the GVC is performed here by the technique that one of the twoacceleration/deceleration instructions which has a higher absolute valueis adopted by arbitration means; an M+ yaw moment instruction value(M_(z) _(_) _(GVC)) based on a lateral jerk, especially on the time rateof change G_(ys) _(_) _(dot) of the lateral acceleration measurementvalue; a yaw moment instruction value (although this exhibits a shapesimilar to that of the lateral jerk, it becomes a signal delayed incomparison with M_(z) _(_) _(GVC) from a relationship with a thresholdvalue and so forth) M_(z) _(_) _(ESC) by the ESC; and a substantialmoment instruction value (Mzc) in which arbitration of the momentinstruction value of the ESC and the M+ yaw moment instruction value(M_(z) _(_) _(GVC)) is performed here by the technique which adopts thatone of the two moment instruction values which has a higher absolutevalue.

A basic hypothetical scene of FIG. 18 is similar to that of FIG. 1. Ageneral traveling scene that the vehicle approaches and leaves a corneralong a straight road A, a transit section B, a steady turning sectionC, another transit section D and another straight road E is assumed.However, FIG. 18 indicates a situation that such a behavior variation ina spinning direction as depicted in FIG. 11 arising from a suddenvariation of the road surface or the like midway of turning (forexample, in the proximity of the point 4 in FIG. 1) occurs. At thistime, a situation is indicated that, although the driver steering angledoes not vary (and therefore also the lateral acceleration estimationvalue G_(ye) assumes a steady value), the measurement lateralacceleration drops once and a behavior variation occurs.

Although a lateral jerk is generated in such a situation as justdescribed, by adopting the method disclosed in JP-2011-105096-A, it ispossible to prevent, when it is decided that the lateral jerk increasesto the proximity of the friction limit, the GVC instruction value (G_(x)_(_) _(GVC)) from being generated in the proximity of a behaviorchanging point by correcting the absolute value of the longitudinalacceleration instruction value of the GVC to zero or a value lower thanthat before the correction.

Further, in FIG. 18, the deceleration instruction G_(x) _(_) _(DRV) ofthe driver is generated (brake beforehand) before the steering angle isincreased, and the brake is released before steady turning and thedriver has no acceleration/deceleration intention during steady turningand also during occurrence of a behavior variation. Further, when thecar is leaving the corner, the brake begins to be released, and alsoafter the corner is left, the vehicle is accelerated. If the brake isreleased before steady turning, the load having moved to the frontwheels is lost. Thus, promotion of the yaw motion and the lateralacceleration depicted in FIG. 12 cannot be expected, resulting in thatthe vehicle may be displaced to the outer side from the target line.With the substantial deceleration instruction G_(XC), both ofdeceleration from a point before a corner by the driver and a turnpromotion effect by the GVC are obtained. When the car is leaving acorner, a stabilization improvement effect by the GVC acts, andsimultaneously, acceleration up to the speed intended by the driver canbe implemented.

Regarding the moment control, since the M+ yaw moment instruction valueis generated basically on the basis of the lateral jerk, a turnpromotion moment and a restoration moment are generated at the time ofstarting a turn and leaving the turn. Therefore, improvement indrivability and improvement in stability can be achieved. What is to benoticed here is that, if the moment instruction value is renderedoperative from the normal region, then the phase of the yaw response tothe steering angle input advances by a great amount, and generation of alateral acceleration which serves as a roll moment is delayedrelatively. Consequently, in comparison with a state where no control isinvolved, a variation is provided to the consistency of the combinationof the yaw and the roll, and the anti-dive lift force of the suspensionis rendered unbalanced between the left and the right, resulting ingeneration of a vehicle behavior variation at the time of control.Accordingly, at least at a place where the coefficient of friction ishigh such as a dry asphalt road, such countermeasures as to lower thegain or not to perform control only for the turn promotion side may betaken.

Further, in a situation in which a behavior variation occurs, a lateraljerk of a sign opposite to that of the lateral acceleration is generateddue to a variation in balance between the sum total of the tire lateralforces and the centrifugal forces as depicted in FIG. 11. Accordingly,by controlling the yaw moment on the basis of the Formula 21, spinprevention or reduction can be anticipated. What is to be noticed hereis the control instruction when the vehicle comes to be stabilized,namely, when the lateral acceleration restores (in the figure, positivevalues are assigned for a turn promotion direction). At this time, inthe case of a vehicle having a small static margin, there is thepossibility that the vehicle which comes to be stabilized once may bedestabilized. In that case, a filter process may be applied so that sucha moment instruction of a high frequency in the turn positive directionmay not be accepted. Alternatively, in the first place, a momentinstruction in the turn positive direction may not be accepted so thatonly a restoration moment may be exclusively applied as depicted in FIG.9.

In a situation that a behavior variation occurs, naturally a momentinstruction by the ESC operates. Accordingly, since the vehicle isstabilized by a restoration moment substantially same as the behaviorvariation by the M+ instruction, the moment instruction by the ESCdecreases. After all, by selecting a higher one of the M+ yaw momentinstruction value and the yaw moment instruction value by the ESC asM_(zc), control shortage does not occur and the safety can be secured.

It is to be noted that, since four-wheel independent braking and drivingcontrol is possible, by distributing driving forces equal to one sidebraking forces generated by the moment instruction value equally to thefour wheels, it is possible to prevent occurrence of acceleration anddeceleration even if the moment is controlled. This mechanism isdepicted in FIGS. 19A and 19B.

If a moment instruction M_(zc) based on lateral slip information and alateral jerk is determined by the ESC and the M+ control (in FIG. 19A, acounterclockwise moment), then, in order to implement this,braking/driving forces (whose sign is the negative) of Ffl and Frl areapplied to the front and rear wheels on the left side so as to satisfy arelationship of the Formula 22.

$\begin{matrix}{M_{zc} = \frac{\left( {F_{fl} + F_{rl}} \right)d}{2}} & \left\lbrack {{Formula}\mspace{14mu} 22} \right\rbrack\end{matrix}$

Consequently, a deceleration represented by the Formula 23 is generatedon the vehicle.

$\begin{matrix}{G_{x\_ M} = \frac{F_{fl} + F_{rl}}{m}} & \left\lbrack {{Formula}\mspace{14mu} 23} \right\rbrack\end{matrix}$

On the other hand, if an acceleration/deceleration instruction G_(xc)based on a lateral jerk, steer information and a driver's intention isdetermined in accordance with the GVC and a driveracceleration/deceleration instruction (in FIG. 19B, deceleration), thenin order to implement this, braking/driving forces Ffl, Ffr, Frl and Frrare applied to the four wheels so as to satisfy a relationship of theFormula 24 (here, a situation in which four-wheel independent brakingand driving control is possible is assumed).

$\begin{matrix}{G_{xc} = \frac{F_{fl} + F_{fr} + F_{rl} + F_{rr}}{m}} & \left\lbrack {{Formula}\mspace{14mu} 24} \right\rbrack\end{matrix}$

Here, as the simplest correction method for implementingnon-interference of the yaw moment control and theacceleration/deceleration control, a method of the Formula 25 isavailable.

$\begin{matrix}{{\Delta \; F} = {\frac{m}{4}\left( {G_{xc} - G_{x\_ M}} \right)}} & \left\lbrack {{Formula}\mspace{14mu} 25} \right\rbrack\end{matrix}$

If this is distributed equally to the four wheels to determinebraking/driving forces for the four wheels newly, then they arerepresented by the Formula 26.

F _(fl) _(_) _(GVM) =F _(fl) −ΔF, F _(fr) _(_) _(GVM) =−ΔF

F _(rl) _(_) _(GVM) =F _(rl) −ΔF, F _(rr) _(_) _(GVM) =−ΔF  [Formula 26]

If the braking/driving control is performed in this manner, then thevalue of the acceleration/deceleration control becomes equal to theinitial value as following Formula 27.

G _(x) =G _(xc)  [Formula 27]

Also the value of the moment control becomes the initial instructionvalue as following Formula 28.

$\begin{matrix}{M = {\frac{\left( {F_{fl} + F_{rl}} \right)d}{2} = M_{zc}}} & \left\lbrack {{Formula}\mspace{14mu} 28} \right\rbrack\end{matrix}$

Complete decoupling of the yaw moment control and theacceleration/deceleration control can be implemented.

Especially, when the acceleration/deceleration Gxc is controlled tozero, since ΔF becomes negative in accordance with the Formula 24, theleft side wheels are braked and the right side wheels are driven fromthe Formula 25. Where there is some restriction to hardware(implemented, for example, only with a deceleration actuator of the ESCor the like), some deceleration feeling is involved.

As described above, a motion controlling apparatus for a vehicle, inwhich driving forces or braking forces of wheels of the vehicle can becontrolled independently of each other, includes: vehicleacceleration/deceleration instruction (GVC instruction) calculationmeans that determines a vehicle acceleration/deceleration instructionvalue on the basis of a lateral jerk (G_(y) _(_) _(dot)) of the vehicle;first vehicle yaw moment instruction (M+ instruction) calculation meansthat determines a vehicle yaw moment instruction value on the basis ofthe lateral jerk of the vehicle; and second vehicle yaw momentinstruction calculation means (ESC instruction) that determines avehicle yaw moment instruction value from lateral slip information ofthe vehicle. Further, the motion controlling apparatus includes: a firstmode that generates, on the basis of the vehicleacceleration/deceleration instruction value determined from the vehiclelateral jerk by the vehicle acceleration/deceleration instructioncalculation means, substantially equal driving forces or braking forces(equal braking pressures and no difference between left and rightdriving forces, or no difference between left and right driving forces)on left and right wheels from among four wheels of the vehicle tocontrol acceleration/deceleration of the vehicle; a second mode thatgenerates, on the basis of the vehicle yaw moment instruction (M+instruction) value determined by the first vehicle yaw momentinstruction calculation means using the vehicle lateral jerk, differentdriving or braking forces on the left and right wheels from among thefour wheels of the vehicle to control a yaw moment of the vehicle; and athird mode that generates, on the basis of the vehicle yaw momentinstruction (ESC instruction) value determined by the second vehicle yawmoment instruction calculation means using the vehicle lateral slipinformation, different driving or braking forces on the left and rightwheels from among the four wheels of the vehicle to control the yawmoment of the vehicle. Consequently, the yaw moment control inaccordance with the M+(moment plus) instruction functions as control inthe transit region in the cooperation control of the G-Vectoring and theESC (DYC). Thus, motion control for a vehicle which can achieveimprovement in drivability, stability and driving comfort, which couldhave been achieved only by incorporation into the ESC, can beimplemented in a plurality of embodiments, and the technology andapparatus can be provided to a greater number of drivers.

Now, two embodiments are described with regard to working examples whichindicate a hardware configuration and so forth.

Working Example 1

FIG. 23 depicts a general configuration of a working example 1 of themotion controlling apparatus for a vehicle of the present invention.

In the present working example, a vehicle 0 is configured from aso-called by-wire system and does not include mechanical couplingbetween a driver and a steering mechanism, an acceleration mechanism anda deceleration mechanism.

<Driving>

The vehicle 0 is a four-wheel drive vehicle (All Wheel Drive: AWDvehicle) wherein a left rear wheel 63 is driven by a left rear wheelmotor 1 and a right rear wheel 64 by a right rear wheel motor 2 while aleft front wheel 61 is driven by a left front wheel motor 121 and aright front wheel 62 by a right front wheel motor 122.

Here, especially as regards a difference between sources of power suchas electric motors and internal combustion engines, the sources of powerare configured such that, as the most preferable example which indicatesthe present invention or by combination with the four-wheel independentbrakes hereinafter described, the driving forces and the braking forcesfor the four wheels can be controlled freely. In the following, theconfiguration is described in detail.

On each of the left front wheel 61, right front wheel 62, left rearwheel 63 and right rear wheel 64, a brake rotor and a wheel speeddetection rotor are mounted, and a wheel speed pickup is mounted on thevehicle side so that the wheel speed of each wheel can be detected. Theoperation amount of an accelerator pedal 10 by the driver is detected byan accelerator position sensor 31 and is subjected to an calculationprocess by a central controller 40 serving as control means through apedal controller 48. The central controller 40 controls driving forcesand/or braking forces for each of the four wheels independently, and thecalculation process of the central controller 40 includes also the GVC,ESC and M+ control for “improving the drivability and the stability” asthe object of the present invention. A power train controller 46controls output power of the left rear wheel motor 1, right rear wheelmotor 2, left front wheel motor 121 and right front wheel motor 122 inresponse to the amount.

An accelerator reaction force motor 51 is connected to the acceleratorpedal 10, and reaction control is performed by the pedal controller 48on the basis of an calculation instruction of the central controller 40.

<Braking>

A brake rotor is provided for each of the left front wheel 61, rightfront wheel 62, left rear wheel 63 and right rear wheel 64, and acaliper for sandwiching the brake rotor with pads (not depicted) todecelerate the wheel is mounted on the vehicle body side. The brakesystem is of the electro-mechanical type having an electric motor foreach caliper.

Each caliper is controlled by brake controllers 451 (for the front leftwheel), 452 (for the front right wheel) or 453 (for each of the rearwheels) basically on the basis of an calculation instruction of thecentral controller 40. Also a brake pedal reactive force motor 52 isconnected to the brake pedal 11, and reactive force control is performedby the pedal controller 48 on the basis of an calculation instruction ofthe central controller 40.

<Integrated Control of Braking and Driving>

In the present invention, in order to “improve the drivability and thestability”, the GVC generates braking/driving forces substantially equalbetween the left and the right wheels, whereas the ESC and the M+generate braking forces or driving forces which are different betweenthe left and right wheels.

An integrated control instruction in such a situation as described aboveis determined in an integrated manner by the central controller 40, andappropriate control is performed through the brake controllers 451 (forthe front left wheel and the front right wheel) and 452 (for the rearwheels), power train controller 46, left rear wheel motor 1, right rearwheel motor 2, left front wheel motor 121 and right front wheel motor122.

<Steering>

The steering system of the vehicle 0 has a steer-by-wire structure whichdoes not have a mechanical coupling between the steering angle of thedriver and the tire turning angle. The steering system is configuredfrom a power steering 7 including a steering angle sensor (not depicted)in the inside thereof, a steering 16, a driver steering angle sensor 33,and a steering controller 44. The steering amount of the steering 16 bythe driver is detected by the driver steering angle sensor 33 and issubjected to an calculation process by the central controller 40 throughthe steering controller 44. Then, the steering controller 44 controlsthe power steering 7 in response to the amount obtained by thecalculation process.

Further, a steering reactive force motor 53 is connected to the steering16, and reactive force control is performed by the steering controller44 on the basis of an calculation instruction of the central controller40.

The operation amount of the brake pedal 11 by the driver is detected bya brake pedal position sensor 32 and is subjected to an calculationprocess by the central controller 40 through the pedal controller 48.

<Sensors>

Now, a motion sensor group of the present invention is described.

As sensors for measuring a movement of the vehicle in the presentworking example, an absolute vehicle speedometer, a yaw rate sensor, anacceleration sensor and so forth are incorporated. In addition, asregards the vehicle speed and the yaw rate, estimation by a wheel speedsensor is performed, and as regards the yaw rate and the lateralacceleration, estimation using the vehicle speed, steering angle and avehicle motion model and so forth are performed simultaneously.

A millimeter wave ground vehicle speed sensor 70 serving as externalfield information detection means is incorporated in the vehicle 0 suchthat it can detect obstacle information, preceding vehicle informationand succeeding vehicle information and can further detect the velocityV_(x) in the longitudinal direction and the velocity V_(y) in thelateral direction independently of each other. Further, to the brakecontrollers 451 and 452, such wheel speeds of the wheels as describedhereinabove are inputted. An absolute vehicle speed can be estimated byan averaging process of the wheel speeds of the front wheels(non-driving wheels) from among the wheel speeds of the four wheels.

The present invention is configured such that, using the methoddisclosed in JP-1993-16789-A, the wheel speeds and a signal of anacceleration sensor for detecting the acceleration in the vehiclelongitudinal direction are added so that, even when the wheel speeds ofthe four wheels drop at the same time, the absolute vehicle speed(V_(x)) may be measured accurately.

Also a configuration which calculates a difference between the speeds ofthe left and right wheels to estimate the yaw rate of the vehicle bodyis provided, by which improvement of the robust property of a sensingsignal is achieved. Those signals are always monitored as sharedinformation by the central controller 40. The estimated absolute vehiclespeed is compared with and referred to by a signal of the millimeterwave ground vehicle speed sensor 70 such that, when some of the signalssuffers from a trouble, the signals complement each other.

As depicted in FIG. 20, a lateral acceleration sensor 21, a longitudinalacceleration sensor 22 and a yaw rate sensor 38 are arranged in theproximity of the center of gravity.

Further, differentiating circuits 23 and 24 for differentiating theoutputs of the individual acceleration sensors to obtain jerkinformation are incorporated.

Further, a differentiating circuit 25 for differentiating the sensoroutput of the yaw rate sensor 38 to obtain a yaw angular accelerationsignal is incorporated.

While it is depicted such that, in the present working example, adifferentiating circuit is installed in each sensor in order todefinitely indicate the presence of the differentiating circuit,actually the acceleration signals may be subjected to a differentiationprocess after they are inputted directly to the central controller 40and subjected to various calculation processes by the central controller40. A yaw rate estimated from the wheel speed sensors described abovemay be used such that it is subjected to a differentiating process bythe central controller 40 to obtain a yaw angular acceleration of thevehicle body.

Further, a sensor which includes a differentiating circuit and has ajerk output obtained by directly differentiating a signal from adetection element which increases in proportion to an acceleration maybe used in an acceleration sensor unit of the MEMS type, which exhibitsa remarkable progress in recent years. There are many cases in which anacceleration sensor output signal is a signal after passing a low-passfilter for smoothing a signal.

A jerk signal can be obtained which exhibits a less phase delay and ahigher degree of accuracy than those where a signal which passes througha low-pass filter once is differentiated again in order to obtain ajerk.

Or, the jerk sensor which is disclosed in JP-2002-340925-A and candirectly detect a jerk may be used.

Although a longitudinal acceleration sensor, a lateral accelerationsensor, a yaw rate sensor, a differentiator and so forth are depictedexplicitly and independently for the convenience of illustration on thedrawings, they may be configured as a combined sensor 200 which hasfunctions of the sensors accommodated in a housing such thatlongitudinal and lateral accelerations, a jerk, a yaw rate and a yawangular acceleration are outputted directly from the combined sensor200. Furthermore, a function for calculating and outputting anacceleration instruction value (GVC) associated with the lateral motionof the Formula 1 or a moment instruction value (M+) of the Formula 21may be integrated with the combined sensor.

Further, the instructions may be sent on a CAN signal to a brake unit ora driving unit so as to perform the GVC and the moment plus control.

If such a configuration as just described is applied, then only if thecombined sensor is placed on a vehicle, the GVC and the moment pluscontrol can be implemented using an existing brake unit and drivingunit. Furthermore, seamless control from the normal region to the limitregion can be implemented by the ESC.

Further, in the present working example, also a method for estimatingthe lateral acceleration Gy and the lateral jerk G_(y) _(_) _(dot) isadopted. As a method for the estimation, they are estimated on the basisof the steering angle and the vehicle speed. Or, they are estimated fromthe yaw rate detected by the yaw rate sensor and the vehicle speed.

A method for estimating the lateral acceleration estimation value G_(ye)and the lateral jerk estimation value G_(ye) _(_) _(dot) from thesteering angle δ is described with reference to FIG. 21.

First, on a vehicle lateral motion model, the steering angle δ [deg] andthe vehicle velocity V [m/s] are inputted, and the yaw rate r at a timeof steady circular turning with dynamic characteristics omitted iscalculated in accordance with the following Formula 29.

$\begin{matrix}{r = {\frac{1}{1 + {AV}^{2}}\frac{V}{l}\delta}} & \left\lbrack {{Formula}\mspace{14mu} 29} \right\rbrack\end{matrix}$

In the formula above, the stability factor A and the wheel base l areparameters unique to the vehicle and are values determinedexperimentally.

Meanwhile, the lateral acceleration G_(y) of the vehicle can berepresented by the Formula 30 given below using the vehicle velocity V,the lateral slip angle rate of change β_(—dot) of the vehicle and theyaw rate r.

G _(y) =V({dot over (β)}+r)≠V·r  [Formula 30]

β_(—dot) represents a motion within a linear range of the tire force andis a quantity which is so small that it can be omitted.

Here, the yaw rate r whose dynamic characteristics are omitted asdescribed above and the vehicle velocity V are multiplied to calculatethe lateral acceleration G_(ye-wod). This lateral acceleration does nottake dynamic characteristics of the vehicle which has a response delaycharacteristic in a low frequency region into consideration.

This arises from the following reason. To obtain the lateral jerkinformation G_(y) _(_) _(dot) of the vehicle, the lateral accelerationG_(y) is differentiated for discrete time. In short, it is necessary toperform a time differentiating process of a lateral accelerationmeasured by a lateral acceleration sensor to calculate the lateral jerkinformation G_(y) _(_) _(dot). At this time, a noise component isstrengthened. Although it is necessary, in order to use the signal incontrol, to pass the signal through a low-pass filter (LPF), this givesrise to a phase delay. Therefore, a method that an acceleration fromwhich dynamic characteristics are removed and which has an earlier phasethan an original acceleration is calculated and then subjected todiscrete differentiation, after which a resulting value is passedthrough an LPF of a time constant T_(lpfe) is adopted to obtain a jerk.This may be considered that dynamic characteristics of the lateralacceleration is represented by a delay by the LPF and the resultingacceleration is merely differentiated. Also the lateral accelerationG_(y) is passed through an LPF of the same time constant T_(lpf).Consequently, the dynamic characteristics are provided also to theacceleration, and although a figure is omitted, it has been confirmedthat, within the linear range, an actual acceleration response can berepresented well.

As described above, the method of calculating the lateral accelerationG_(y) and the lateral jerk G_(y) _(_) _(dot) using a steering angle isadvantageous in that it suppresses the influence of noise and also theresponse delay of the lateral acceleration G_(y) and the lateral jerkG_(y) _(_) _(dot) is reduced.

However, since the present estimation method omits lateral slipinformation of the vehicle and ignores a nonlinear characteristic of thetires, when the lateral slip angle becomes great, it is necessary tomeasure and utilize an actual lateral acceleration of the vehicle.

FIG. 22 illustrates a method of obtaining a lateral acceleration G_(ys)and a lateral jerk G_(y) _(_) _(dot) for control by use of, for example,a detection element signal G_(yeo) of a MEMS element 210 in the combinedsensor 200. Since a noise component arising from unevenness of the roadsurface or the like is included, it is necessary to pass also thedetection element signal through a low-pass filter (time constantT_(lpfs)) (this is not dynamics compensation).

In the combined sensor 200, the lateral acceleration G_(ys) and thelateral jerk information G_(y) _(_) _(dot) for control obtained may beused to calculate a GVC instruction from the Formula 1 by anacceleration/deceleration instruction calculation unit and output anacceleration/deceleration instruction value G_(xt) or calculate a momentinstruction value (M+) from the Formula 21 and output a momentinstruction value M_(z+).

To achieve both merits in such estimation and measurement of the lateralacceleration and jerk as described above, the present working exampleadopts a method that both signals are used complementarily as depictedin FIG. 23.

An estimation signal (indicated by a subscript e which representsestimated) and a detection signal (indicated by a subscript s whichrepresents sensed) are multiplied by a variable gain based on lateralslip information (lateral slip angle R, yaw rate r or the like) and thenare added.

This variable gain K_(je) (K_(je)<1) for the lateral jerk estimationsignal G_(ye) assumes a high value within a range where the lateral slipangle is small, but is changed so as to have a lower value as thelateral slip increases. Further, the variable gain K_(js) (K_(js)<1) forthe lateral jerk detection signal G_(ys) _(_) _(dot) assumes a low valuewithin a range where the lateral slip angle is small, but is changed soas to have a higher value as the lateral slip increases.

Similarly, the variable gain K_(ge) (K_(ge)<1) for the lateralacceleration estimation signal G_(ye) assumes a high value within arange where the lateral slip angle is small, but is changed so as tohave a lower value as the lateral slip increases. Further, the variablegain K_(gs) (K_(gs)<1) for the lateral acceleration detection signalG_(ys) assumes a low value within a range where the lateral slip angleis small, but is changed so as to have a higher value as the lateralslip increases.

By adopting such a configuration as described above, acceleration andjerk signals in which noise is reduced over a range from the normalregion in which the lateral slip angle is small to the limit region inwhich the lateral slip is great and which is suitable for control can beobtained. It is to be noted that the gains of them are determined usinga function for lateral slip information or a map. Or, even if selecthigh of absolute values is performed simply in such a manner as depictedin FIGS. 15 and 18, it was confirmed successfully that practical use isanticipated sufficiently.

So far, the apparatus configuration and the method for estimating alateral acceleration and a lateral jerk (which may be included as alogic in the combined sensor 200 in which the sensors in FIGS. 19A and19B are integrated or in the central controller 40) of the first workingexample of the motion controlling apparatus for a vehicle according tothe present invention have been described.

Now, a system configuration including the logic according to the presentinvention is described with reference to FIG. 24.

FIG. 24 schematically depicts a relationship between a calculationcontrol logic 400 of the central controller 40 serving as control meansand an observer which estimates (although calculation is performed inthe central controller 40) a lateral slip angle on the basis of thevehicle 0, sensors and signals from the sensors. The entire logic isroughly configured from a vehicle motion model 401, a G-vectoringcontrol calculation unit 402, an M+ control calculation unit 403, an ESCcontrol calculation unit 404 and a braking force/driving forcedistribution unit 405.

In particular, the central controller 40 serving as control meansgenerates an acceleration/deceleration instruction and a momentinstruction on the basis of a detected steering angle δ and vehiclespeed V and an acceleration/deceleration instruction G_(x) _(_) _(DRV)of the driver. The acceleration/deceleration instruction is generated byacceleration/deceleration instruction generation means (vehicle motionmodel 401, G-vectoring control calculation unit 402 and an adder of adriver acceleration/deceleration instruction). In particular, theacceleration/deceleration instruction is generated as a controlinstruction value by adding a driver acceleration/decelerationinstruction to a target longitudinal acceleration generated on the basisof the steering angle and the vehicle velocity. Further, the brakingforce/driving force distribution unit 405 serving as drivingforce/braking force distribution means determines driving forces ordriving torques for the wheels and/or distribution of driving forces orbraking torques.

The vehicle motion model 401 estimates, from the steering angle δinputted from the driver steering angle sensor 33 and the vehiclevelocity V, an estimation lateral acceleration (G_(ye)), a target yawrate r_(t) and a target lateral slip angle β_(t) using the Formula 2 andthe Formula 3. In the present working example, the target yaw rate r_(t)is set so as to be equal to a yaw rate r_(δ) determined from steering.

For the lateral acceleration and the lateral jerk to be inputted to theG-vectoring control calculation unit 402 and the M+ control calculationunit 403, the signal processing apparatus (logic) 410 whichcomplementarily uses signals of them is adopted as depicted in FIG. 23.

The G-vectoring control calculation unit 402 determines a componentassociated with the vehicle lateral motion at present from within thetarget longitudinal acceleration instruction G_(x) _(_) _(GVC) inaccordance with the Formula 1 using the lateral acceleration and thelateral jerk inputted thereto. Further, the G-vectoring controlcalculation unit 402 adds G_(x) _(_) _(DRV) which is anacceleration/deceleration intention of the driver to calculate a targetlongitudinal acceleration instruction G_(Xc) and outputs the targetlongitudinal acceleration instruction G_(Xc) to the brakingforce/driving force distribution unit 405. Naturally, select high may beapplied to the acceleration and jerk values similarly as in FIG. 18. Inother words, the target longitudinal acceleration instruction G_(x) _(_)_(GVC) is calculated on the basis of the estimation lateralacceleration, which is calculated from the steering angle and thevehicle velocity, and the lateral jerk, which is calculated from theestimated lateral acceleration.

Similarly, the M+ control calculation unit 403 determines a targetmoment in accordance with the Formula 21 using the lateral accelerationand the lateral jerk. In other words, the target moment instructionM_(Z+) is calculated on the basis of the estimation lateral accelerationcalculated from the steering angle and the vehicle velocity, and thelateral jerk calculated from the estimated lateral acceleration.

Then, the ESC control calculation unit 404 calculates a target momentM_(z) _(_) _(ESC) on the basis of the deviations Δr and Δβ between thetarget yaw rate r_(t) (r_(δ)) and target lateral slip angle β_(t) andthe actual yaw rate and actual (estimated) lateral slip angle, and addsthe target moment M_(z) _(_) _(ESC) to the target moment instructionM_(Z+) calculated as above and outputs a resulting instruction to thebraking force/driving force distribution unit 405. Naturally, selecthigh may be applied to the two moment instruction values similarly as inFIG. 18. The target moment M_(z) _(_) _(ESC) is calculated on the basisof the steering angle, the vehicle velocity and the yaw rate and thelateral slip angle of the vehicle.

The braking force/driving force distribution unit 405 is configured suchthat it determines initial basic braking and driving forces (F_(xfl)_(_) _(o), F_(xfr) _(_) _(o), F_(xrl) _(_) _(o), and F_(xrr) _(_) _(o))for the four wheels of the vehicle 0 as depicted in FIG. 25 on the basisof the target longitudinal acceleration instruction G_(Xc) which is anacceleration/deceleration instruction and the target yaw moment M_(zc).Naturally, the braking or driving forces are distributed so as to allowdecoupling of the yaw moment control and the acceleration/decelerationcontrol.

Now, a vehicle motion when diagonal distribution control of the presentinvention is applied is described assuming particular traveling.

A hypothetical scene of FIG. 26 is similar to that of FIG. 18 (FIG. 1),and a situation that, at a point 4 in a steady turning section C fromamong general traveling scenes of approaching and leaving a cornerincluding a straight road A, a transient section B, a steady turningsection C, another transient section D and a straight section E, abehavior variation occurs. At a lower stage, braking/driving forces ofthe front outer, front inner, rear outer and rear inner wheels aredepicted.

First, at a time of deceleration by the driver before the curve, brakingforces by the brakes for the four wheels having an equal pressure acts(there is no difference between the turning inner and outer wheels). Ata stage at which a lateral acceleration increases in response to aninput of a steering angle, the braking forces for the front and rearwheels on the turning inner side has a high value so that a moment forpromoting the turn is generated. Further, if the lateral accelerationincreasing stage passes and steady turning is entered, then thebraking/driving forces reduce to zero (also the lateral jerks are zero).

Here, if a behavior variation of a spinning tendency occurs, then arestoration moment in the opposite direction to the turning direction isrequired to prevent the spinning. To this end, braking forces areapplied to the front and rear wheels on the turning outer side so that aclockwise moment is obtained. Further, since the instruction foracceleration/deceleration is zero, driving forces are applied to thefront and rear wheels on the turning inner side. Consequently, thebraking forces and the driving forces in the forward/backward directionare balanced, and the acceleration/deceleration of zero can beimplemented. Further, since also the driving forces become a clockwisemoment, a greater stabilization moment is obtained and improvement ofthe spinning preventing performance is achieved (at this time, aconfiguration for returning regenerative energy obtained by braking tothe driving side may be adopted).

Further, when the car is leaving a curve, driving forces are distributedso as to be applied to the front and rear wheels on the turning outerside to provide a moment on the restoration side so that the straightlyadvancing state may be restored at an early stage. Naturally, after thestraightly advancing state is entered fully, the driving forces aredistributed so that a left/right difference may not occur.

As described above, the central controller 40 of such a vehicle 0 inwhich four-wheel independent braking/driving control is possible asdepicted in FIG. 20 implements Hybrid+ Enhanced control (braking/drivingcontrol) of acceleration/deceleration control by a G-Vectoring controlinstruction (and a driver control instruction) based on a lateral jerk,yaw moment control by a moment plus (M+) control instruction based onthe lateral jerk and yaw moment control by an ESC control instructionbased on lateral slip information. Consequently, a behavior variationsuppression effect which does not involve acceleration/deceleration canbe obtained together with improvement in drivability and stability.

Further, since the vehicle includes motors (left rear wheel motor 1,right rear wheel motor 2, left front wheel motor 121 and right frontwheel motor 122) for generating braking forces or braking torques as inthe present working example, the vehicle may be configured such that itincorporates regeneration means (not depicted) for regenerating electricpower generated when braking forces or braking torques is generated bythe electric motors so that energy involved in the motion control can berecovered.

Also where the Hybrid+ control is considered only from brake controlwhich does not involve driving, by incorporating all of a G-Vectoringcontrol instruction calculation unit, a moment plus (M+) controlinstruction calculation unit and an ESC control instruction calculationunit into one controller, for example, into an ESC of premiumspecifications similarly to the central controller 40 describedhereinabove, similar effects can be achieved although some decelerationis generated. However, this comes to utilize a so-called brake LSDeffect, Torque-Vectoring effect such as to apply braking or applydriving forces to one side of the driving wheels having a differentialgear.

The control effect of the working example which is an ideal mode aredescribed above. In the following, that another effect which makespossible the Hybrid+ control to which moment plus control of the presentinvention is added, namely, an effect that a superior control effect isobtained even in a state in which the hardware configuration isrestricted, is achieved is demonstrated using results of experiments.

Working Example 2

FIG. 27 depicts a control configuration of a second embodiment of thepresent invention. Basically, the second embodiment is configured suchthat a deceleration instruction by the GVC and a moment instruction bythe M+ are applied to a deceleration port 901 and a moment port 902provided in a premium ESC 90. An original movement of the ESC is thensubjected to moment control using lateral slip information. Yetactually, as depicted in FIG. 28, the ESC control logic itself isincorporated as conventional control in the main body of the premium ESCtogether with an estimation logic for the lateral slip angle β and soforth. Information is then sent to the deceleration port 901 and themoment port 902 from an external controller such as an ADAS controller91 through a CAN connection.

In the ADAS controller 91, a control changeover function is incorporatedwhich is ready for an ITS such that, for example, when an obstacle isfound on the basis of various kinds of external information obtainedfrom a stereo camera or navigation information or through communicationwith the outside, the gain of the GVC or the M+ is changed to a ratherhigh value. By virtue of the control changeover function, in a normalstate, it is possible to operate the control with a setting in which theuncomfortable feeling in a normal region is reduced, but when anobstacle exists, it is possible to operate the control with a controlsetting in which the emergency avoidance performance is improved, andthe safety can be improved significantly. Further, the second embodimentis configured such that the acceleration/deceleration instruction isdecreased to zero when external information including one of obstacleinformation, preceding vehicle information and succeeding vehicleinformation is obtained so as to avoid a collision, a rear-end collisionand so forth.

It is needless to say that an acceleration operation instruction and abrake operation instruction from the driver are inputted to the ADAScontroller 901 (though not depicted). The acceleration instruction ofthe GVC is adjusted to zero when the brake operation instruction fromthe driver is inputted whereas the deceleration instruction of the GVCis adjusted to zero when the acceleration operation instruction from thedriver is inputted. Thus, a vehicle which complies with an intention ofthe driver is implemented.

Since the motion control logic is incorporated in the ADAS controller towhich external information is collectively transmitted, such meticulouscontrol as described above can be implemented readily.

The superiority of the present invention is demonstrated below using aresult obtained when a test was performed on a compacted snow road usinga test vehicle which embodied the second working example of the presentinvention.

FIG. 29 depicts an outline of the test vehicle which embodied theconfiguration depicted in FIGS. 27 and 28. The vehicle is an FR typefive-speed AT vehicle having an exhaust amount of 2.5 liters. As the ESCunit, a model of premium specifications is incorporated. The ESC unit isconfigured such that a general-purpose controller compatible with theADAS controller is used to write a GVC instruction value and an M+instruction value into ports for a deceleration instruction value and amoment instruction value of the Vehicle CAN system, and hardware is notremodeled. In comparison with closed communication in the ESC unit, theCAN communication has a disadvantage that the communication speed isvery low. Conversely, if an advantage in controlling a vehicle movementis obtained with such a configuration as just described, then it can bedemonstrated that a control effect is obtained with any of theconfigurations depicted in FIG. 5 (in whichever one of the controllerconnected to each other by the CAN the logics of the GVC and the M+ areincorporated). Consequently, high-quality motion control according tothe present invention using the plurality of embodiments can beimplemented and the concerned technology and apparatus can be providedto a greater number of drivers.

Although state variables such as a wheel speed or lateral slip angleinformation and control amounts such as a moment or a deceleration inthe ESC cannot be monitored, it was able to measure a flag indicatingthat the ESC (VDC) is operating. The software and controller developedwith such a configuration as described above do not require remodelingof hardware and software and also expansion thereof to a vehicle havinga different actuator can be performed readily. Consequently, they havean advantage that development thereof at a low cost is possible.

Test Contents

Such following three tests as depicted in FIG. 30 were performed inorder to quantitatively evaluate the second working example of thepresent invention.

L Turn Test

An L turn test is such a test mode showing control interfering and itsending principally at the time of ESC development, the test mode furtherinducing slow spinning due to loose steering. The L turn test can beregarded as a standard menu which has been performed irrespective of adry road or a snow road at an initial stage of the development of theGVC. In the case of a compacted snow road, such a behavior occurs that,even if steering is performed smoothly and slowly, the rear side of thevehicles starts shaking on occasions when they enter the road at a speedaround 60 km/h. Evaluation of line traceability can be performed bymeasuring a locus using the GPS together with measurement of thesteering angle input and various condition amounts. Principally checkingdriver steering for performing simple right angle cornering and aresponse and a phase of the yaw rate in response to the driver steeringevaluates the drivability and so forth of the vehicle and control by thedriver. At the present time, an entering permitting speed and acorrection steering amount at the time of an L turn were evaluated.

Lane Change Test

A single lane change, being high frequency steering which assumesemergency avoidance, is for evaluating an operation tracking performance(traceability) and behavior stability (convergence property). Althoughthe interference timing and amount should be tuned on the basis ofevaluation of a test driver who exhibits a less dispersion in operation,it was determined at this time to simply evaluate only whether a lanechange was successful. Further, for the convenience of the space,description is given only of limited control specifications (where theDVC, ESC and W+ are incorporated [Hybrid+] and only the ESC [equivalentto a normal vehicle] is incorporated).

Handling Course Test

Comprehensive evaluation of a feeling and so forth which cannot bedigitized is performed. At this time, the vehicle did not travel at itsmaximum speed with possible risks; it was intended to drive the vehicleto travel in conformity with vehicle characteristics implemented bycontrol while a sufficient margin is taken.

Contents of Controls Placed in Tests

Since the ESC, GVC and M+ controls were involved at this time, controlevaluation of ON/OFF of them, namely, of 2̂ 3=8 controls (FIG. 31), wasperformed. Although a vehicle which does not incorporate the ESC thereinis not at all productized actually (legally as well), since the ESC maypossibly be turned OFF within responsibility of the driver, also a testfor a combination with ESC OFF was conducted. Further, in (d) among thecontrols, the GVC is ON, the ESC is ON and the M+ is OFF. In the case ofthis configuration, a GVC instruction is transmitted as a CAN signalfrom a different controller to the ESC, and seamless control is notconstructed because the intervention threshold value and so forth of theSC are not changed. Accordingly, this is described as (d) Differentcontroller hybrid control.

The most significant comparison is between the case (a) where allcontrols are involved (Hybrid+ control of the invention) and the case(b) where a vehicle “equivalent to vehicle with normal ESC” is employed.The case (a) is an image of the best mode which can be implemented bythe second working example of the present invention.

Actual Vehicle Test Result

L Turn Test Result

L turn test results of the cases (a) to (h) of FIG. 31 are depicted inFIGS. 32 to 35. Evaluation points of them are described.

(1) Time Series Data of Steering Angle and Yaw Rate

It can be evaluated in what manner the yaw rate varies together with asteering angle variation. For example, within a range where the steeringangle is small, the yaw rate has a substantially linear responserelationship. However, as the steering angle increases, separation fromthis relationship appears. Further, when the steering angle exceedsalmost 100 degrees, also the lateral slip angle of the front wheelsexceeds 6 degrees from the relationship of the gear ratio, andtherefore, a nonlinear characteristic comes to appear. The drivabilitycan be comprehended from the relationship between the steering anglevariation and the yaw rate variation.

(2) Lissajous Waveform Initial Speed of Steering Angle and Yaw Rate

Although close to the foregoing, a nonlinearity of the yaw rate withrespect to the steering angle can be comprehended. Further, the steeringrange during an L turn becomes obvious, and it is targeted that thesteering range falls within a range where it is in the positive. Inorder to secure the drivability, it is desirable that an oblique singleline is indicated in the first quadrant.

(3) Longitudinal and Lateral Accelerations and ESC, M+ Flag

The superiority in course traceability can be compared in a situationwhere the lateral acceleration increases. Naturally, the traceability islower where the lateral acceleration rises more rapidly. Unless thelateral acceleration rises, the driver will have to do nothing butcontinue to increase the steering angle. It is recognized that, when theGVC is operative, a deceleration is generated in association with thelateral motion. Further, from flags of the individual controls, it canbe recognized whether or not the control is operating when the lateralacceleration drops (the lateral jerk is in the negative).

(4) “g-g” Diagram

A link between the longitudinal and lateral accelerations can berecognized. Preferably, the diagram exhibits a smooth transition in acurved state.

(5) Vehicle Velocity Transition

It can be recognized at which timing the velocity is reduced. Further,an initial velocity at a time of entrance into an L turn can berecognized.

(6) Vehicle Route

Naturally, it is better that the course be traced at a right anglewithout a swing.

In the following, evaluation of the respective cases is describedsuccessively in comparison with the others. It is to be noted that, inan event where only the ESC is involved, the test result when theentering speed was 55 km/h while the vehicle departed from the coursewas adopted; the other test results were obtained at the entering speedof 60 km/h.

(a) Hybrid+ Control (ESC ON, GVC ON, M+ ON)

Both the steering angle and the yaw rate remain within small ranges. Thepresent data was selected from that of a case in which spinning wasabout to occur at a late stage of turning (in order to check operationof the moment control). The steering angle vs. yaw rate remains withinthe first quadrant, no correction steering in the negative direction isfound, and the linearity is maintained. Even if a sudden increase of theyaw rate occurs, since this is stopped accurately by the M+ control andthe ESC, counter steering by the driver is little performed. Thetrajectory indicates that the vehicle travels at a clean right anglealong the L turn.

(b) Vehicle “Equivalent to Vehicle with Normal ESC” (ESC ON, GVC OFF, M+OFF)

A so-called slow spin state is exhibited. Since the yaw rate does notincrease even if the steering angle is increased, in order for thevehicle to travel along the course, the steering angle is increasedsteadily. The yaw rate is soon placed into a state in which it does notstop and correction steering is performed hastily toward the negativedirection. The ESC does not operate until the correction steering comesto the negative direction, and as a result, the vehicle exhibits amotion causing swinging to right and left. The linearity of the yawresponse to the steering angle gives rise to a great phase differenceparticularly to the return side, resulting in a complicatedcharacteristic. It is supposed that, at a point of time at which a largesteering angle (proximate to 150 degrees) is required for the firsttime, a delay of the correction steering is caused.

(c) GVC Off (ESC ON, GVC OFF, M+ ON)

Since the GVC does not operate, the yaw rate does not follow up thesteering angle similarly as in the case of (b) a vehicle “equivalent tovehicle with normal ESC”, and therefore, the steering angle graduallyincreases, and thereafter, correction steering is applied toward theopposite direction. By virtue of the M+ control, the negative correctionsteering amount is smaller than that in the case of (b) (−150 degrees to−110 degrees).

(d) Different Controller Hybrid+ Control (ESC ON, GVC ON, M+ OFF)

Although the steering angle at an initial stage of turning wassuccessfully decreased (smaller than 100 degrees) by the GVC, theoversteer in the latter half was not successfully stopped only by theESC, and as a result, reversal of the yaw rate occurred. Since thesteering angle is small, the fluctuation is less than that in the casesof (b) and (c). In other words, it is indicated that even theconfiguration for transmitting an instruction of the GVC from adifferent controller in the form of a CAN signal whose communicationspeed is low can exhibit an effect of the GVC definitely and has moresignificance than the vehicle which involves only the ESC.

(e) GVC & M+ (ESC OFF, GVC ON, M+ ON)

The steering angle at an initial stage of turning is reduced by the GVC,the rise of the yaw rate is good, and they are stabilized by the momentalso in the latter half. The Lissajous waveform of the steering anglevs. yaw rate is almost linear and passes the same place at the go andreturn. Thus, it is hard to feel the low friction road in the driving.The g-g″ diagram exhibits a movement of a curved line, and a preferablefeeling was implemented successfully. This signifies that, within arange until the ESC operates, high-quality control can be anticipated,and it can be recognized that an intended control performance isimplemented successfully.

(f) Only GVC (ESC OFF, GVC ON, M+ OFF)

Although there is no problem at an initial stage of turning, the rearside of the vehicle still begins to swing in the latter half, and as aresult, correction steering occurs toward the opposite direction. Thesteering speed is rather low. Since the deceleration by the GVC does notappear by a great amount, the vehicle velocity is higher than that inthe case of (e).

(g) Only Moment (ESC OFF, GVC OFF, M+ ON)

Since the steering is not effective as expected, the steering anglebecomes excessively great and reverses in the latter half.

(h) No Control (ESC OFF, GVC OFF, M+ OFF)

Since no control is involved, driving is performed carefully, and theincrease of the steering angle is relatively small. A reversal in thelatter half occurs ordinarily. Since the moment control for restorationis not involved, correction by a little greater amount than that in thecase of (g) is performed.

From the results described above, it was confirmed that the concept thatthe understeer is suppressed to decrease the steering angle by the GVCand thereafter the oversteer is reduced by the M+. By virtue ofcombination of the ESC and the present control (GVC & M+), it waspossible to enhance the entering angle by 10 percent, increase thesafety margin and eliminate correction steering in the negativedirection thereby to improve the drivability and the safety, incomparison with the ordinary ESC.

Lane Change Test Results

The lane change test results indicate reflection of the motionperformance described in the foregoing description of the L turn, andtherefore, those only of the Hybrid+ control (ESC ON, GVC ON, M+ ON) and(b) A vehicle “equivalent to vehicle with normal ESC” is presented (FIG.36). The initial velocity is 60 km/h as read on a meter.

(a) Hybrid+ Control (ESC ON, GVC ON, M+ ON)

The vehicle can change lanes almost without any problem although, at thetime of secondary steering back, the rear side exhibits a behavior tothe reverse side a little.

(b) Vehicle “Equivalent to Vehicle with Normal ESC” (ESC ON, GVC OFF, M+OFF)

The lateral movement performance is poorer than that of the case of (a).It is necessary to keep a large steering angle for a long period oftime. Within this period, the yaw rate is vibratory (in the proximity ofa natural frequency of the vehicle). Therefore, on the secondary side,also the correction steering has a similar frequency, and a DIS (DriverInduced Oscillation) is exhibited. Since a lateral movement is possiblein (a), the vehicle is steered back immediately. The vehicle results insuccess in lane change without natural vibration of the vehicle.

Handling Road Traveling Test Results

FIG. 37 depicts data when the vehicle traveled on a handling road inregard to (a) Hybrid+ control (ESC ON, GVC ON, M+ ON) and (b) a vehicle“equivalent to vehicle with normal ESC” (ESC ON, GVC OFF, M+ OFF). Inboth cases, traveling suitable for the vehicle characteristicimplemented by control was intended with a sufficient margin. As aresult, as seen from the vehicle velocities, (a) shows more disciplineddriving in that the average vehicle velocity was higher by more than 5km/h and the velocity difference was greater. In (a), although thevelocity was higher, the ESC operated only at two locations: around 45seconds and 98 seconds. Especially around 98 seconds, the vehicle was ata frozen downlink reverse bank corner, and the result is that the ESClittle operated. If the “g-g” diagram is viewed, then it can berecognized that longitudinal and lateral accelerations were successfullygenerated evenly over a wide range in comparison with (b).

Although the evaluation was performed by a plurality of drivers (threedrivers), the specifications of (a) were superior in feeling to those of(b). It is considered that this is because, with the specifications of(b), the steering is less liable to work at an entrance of a corner andit is necessary to increase the steering angle cautiously. Once thesteering angle starts being larger, the ESC causes abrupt deceleration.Although the traveling was performed with other specifications of (h) Nocontrol, (d) only Moment is OFF (different controller hybrid control)and (e) GVC & M+, which indicated a good feeling in the L turn, the testresults of them are omitted due to the limitations of the space.

To visualize the feelings of the control specifications, such a “Jx-Jy”diagram (longitudinal jerk vs. lateral jerk) and a newly devised“δ_(—dot)-r_(—dot)” (steering speed vs. yaw angle speed) diagram asdepicted in FIG. 38 were drawn.

It is considered that a distribution diagram of a jerk demonstrates thedegree of linkage of the longitudinal motion and the lateral motion. Asituation of comfortable riding refers to one where condition amountsgather in the proximity of the origin. Since (a) exhibits a higheraverage speed than (b), although the comparison conditions are not good,the degree of concentration to the origin is higher than that of thenormal vehicle of (b). Moreover, (e) GVC & M+ which exhibited a goodfeeling is higher in degree of concentration to the origin than (b).This is because, within a range in front of the limit at which the ESCis not operated, similar control to that in (a) can be expected.

Further, in (d) OFF Moment (different controller hybrid control),although the condition amounts are concentrated to the origin to somedegree in comparison with (b), a trajectory (traced by a plural numberof times) like a circle is found in the first quadrant. This signifiesthat there is a portion at which a lateral motion and a longitudinalmotion occur abruptly (while they are linked with each other). Anevaluation of the M+(moment plus) control invented newly at this timewill now be checked on the “δ_(—dot)-r_(—dot)” diagram. It is consideredthat, also on the diagram, where the condition amounts are spaced farfrom the origin and exist particularly in the second quadrant or thefourth quadrant, the vehicle control is difficult. It is consideredthat, if ideally the condition amounts are concentrated on a steadilyincreasing line (whose inclination is represented by K) passing theorigin or in the proximity of the origin, then the vehicle can be driveneasily. This is because it is considered that K is an instant yaw rategain (dr/dδ) with respect to a unit steering amount during a motion(Formula 31).

$\begin{matrix}{K = {\frac{\frac{dr}{dt}}{\frac{d\; \delta}{dt}} \approx \frac{dr}{d\; \delta}}} & \left\lbrack {{Formula}\mspace{14mu} 31} \right\rbrack\end{matrix}$

Where this is fixed in the individual motion states, the vehicle can behandled easily. It can be seen that, in (d) where Moment if OFF(different controller hybrid control), the inclination K is greater thanin (a) and (e). In particular, it can be seen that the inclination K hasa rather peaky characteristic with respect the steering. It isconsidered that this is because the control for compensating for adecrease of the restoration moment is not used and this is a resultwhich demonstrates the effectiveness of the M+ control.

In the above manners, by virtue of the driving stability-feelingevaluation using the two different diagrams where handling road testresults were employed, effects of the individual controls werequantitatively evaluated successfully from a dynamical point of view.This evaluation made it possible to confirm the effectiveness of the GVCand M+ control. Those controls can be implemented by sending aninstruction from a controller equivalent to the ADAS controller to theESC that has a deceleration input port and a moment input port. Sinceperformance of a vehicle with a normal ESC can be improved significantlywithout remodeling, high-quality motion control can be implemented in aplurality of embodiments, and thus the technology and apparatus can beprovided to a greater number of drivers (FIG. 39).

In the foregoing, the yaw moment control (ESC) based on lateral slipinformation, the acceleration/deceleration control (G-Vectoring) basedon a lateral jerk and the control (Hybrid control) of the combination ofthem have been mentioned, and it has been indicated that, fromconstrains of the hardware, “transit control” from a transient state toa limit region is required. Further, basic ideas such as a technologicalbackground and an implementing method regarding the yaw moment control(moment plus: M+) based on a lateral jerk have been presented, and theeffectiveness of the vehicle motion control (Hybrid+) having the threemodes of ESC, GVC and M+ has been presented.

Further, the effectiveness of the present invention has been describedusing the two working examples and actual vehicle test results. In theactual vehicle test results, it has been indicated that a sufficienteffect can also be achieved with a system configuration which uses avehicle CAN of a relatively low communication speed. It has beendemonstrated that, with a system configuration where a plurality ofcontrollers are connected by a CAN signal as well, vehicle motioncontrol having high-quality drivability and stability according to thepresent invention can be implemented.

The present invention makes it possible to achieve the Hybrid+ controlby virtue of: adding, to motion control of a vehicle (Hybrid control ofG-Vectoring and ESC [DYC]), the moment control (M+) for transit betweenthe two types of control which had to be incorporated into ESC, thevehicle improving its drivability, stability, and driving comfort;mounting the G-Vectoring and the M+ at least on a controller connectedby communication; and sending an instruction to the ESC viacommunication. This indicates that the present technology and apparatuscan be provided to a greater number of drivers in a plurality ofembodiments of hardware.

DESCRIPTION OF REFERENCE NUMERALS

-   0: vehicle-   1: left rear wheel motor-   2: right rear wheel motor-   7: power steering-   10: accelerator pedal-   11: brake pedal-   16: steering-   21: lateral acceleration sensor-   22: longitudinal acceleration sensor-   23, 24, 25: differentiating circuit-   31: accelerator position sensor-   32: brake pedal position sensor-   33: driver steering angle sensor-   38: yaw rate sensor-   40: central controller-   44: steering controller-   46: power train controller-   48: pedal controller-   51: accelerator reaction force motor-   52: brake pedal reactive force motor-   53: steering reactive force motor-   61: left front wheel-   62: right front wheel-   63: left rear wheel-   64: right rear wheel-   70: millimeter wave ground vehicle speed sensor

1. A processor for a vehicle, comprising: a vehicle yaw momentinstruction calculator that calculates a vehicle yaw moment instructionvalue on the basis of a lateral jerk of the vehicle; a mode under whichyaw moment of the vehicle is controlled on the basis of the vehicle yawmoment instruction value that generates driving forces or drivingtorques and/or braking forces or braking torques of wheels of thevehicle; If the vehicle yaw moment instruction value generates thedriving forces or the driving torques, the driving forces or drivingtorques are different between the left and right wheels; If the vehicleyaw moment instruction value generates the braking forces or the brakingtorques, the braking forces or the braking torques are different betweenthe left and right wheels; wherein the mode operates at least in transitregion between daily region and limit region.
 2. The processor accordingto claim 1, wherein the mode includes one or both of: a 2.1th mode,applied when product of vehicle lateral acceleration and the vehiclelateral jerk is positive, under which a yaw moment on the turningpromotion side of the vehicle is controlled on the basis of a yaw momentinstruction value at a vehicle turning promotion side serving as thevehicle yaw moment instruction value, the vehicle yaw moment instructionvalue being calculated by the vehicle yaw moment instruction calculatorusing the lateral jerk of the vehicle; and a 2.2th mode, applied whenthe product of vehicle lateral acceleration and the vehicle lateral jerkis negative, under which a yaw moment instruction value on the vehiclestabilization side of the vehicle is controlled on the basis of a yawmoment instruction value on the vehicle stabilization side which is thevehicle yaw moment instruction value, the vehicle yaw moment instructionvalue being calculated by the vehicle yaw moment instruction calculatorusing the lateral jerk of the vehicle.
 3. The processor according toclaim 1, further comprising a motor for generating a braking force or abraking torque, wherein the control unit includes a regenerator forregenerating electric power generated when the braking force or thebraking torque is generated by the motor.
 4. The processor according toclaim 1, wherein the vehicle yaw moment instruction value is generatedsuch that turning of the vehicle is promoted when lateral accelerationof the vehicle increases but restores when the lateral acceleration ofthe vehicle decreases.
 5. The processor according to claim 1, whereinthe vehicle yaw moment instruction value is generated such that turningof the vehicle is promoted when steering angle of the vehicle increasesbut restores when the steering angle of the vehicle decreases.
 6. Theprocessor according to claim 1, wherein the vehicle yaw momentinstruction value is generated on the basis of lateral acceleration andthe lateral jerk of the vehicle and a predetermined gain, the lateralacceleration and the lateral jerk being generated from steering angleand velocity of the vehicle.
 7. A processor for a vehicle, comprising: avehicle yaw moment instruction calculator that calculates a vehicle yawmoment instruction value on the basis of a lateral jerk of the vehicle;wherein yaw moment of the vehicle is controlled under mode on the basisof the vehicle yaw moment instruction value that generates drivingforces or driving torques and/or braking forces or braking torques ofwheels of the vehicle; If the vehicle yaw moment instruction valuegenerates the driving forces or the driving torques, the driving forcesor driving torques are different between the left and right wheels; Ifthe vehicle yaw moment instruction value generates the braking forces orthe braking torques, the braking forces or the braking torques aredifferent between the left and right wheels; wherein the mode operatesat least in transit region between daily region and limit region.
 8. Theprocessor according to claim 7, wherein the mode includes one or bothof: a 2.1th mode, applied when product of vehicle lateral accelerationand the vehicle lateral jerk is positive, under which a yaw moment onthe turning promotion side of the vehicle is controlled on the basis ofa yaw moment instruction value at a vehicle turning promotion sideserving as the vehicle yaw moment instruction value, the vehicle yawmoment instruction value being calculated by the vehicle yaw momentinstruction calculator using the lateral jerk of the vehicle; and a2.2th mode, applied when the product of vehicle lateral acceleration andthe vehicle lateral jerk is negative, under which a yaw momentinstruction value on the vehicle stabilization side of the vehicle iscontrolled on the basis of a yaw moment instruction value on the vehiclestabilization side which is the vehicle yaw moment instruction value,the vehicle yaw moment instruction value being calculated by the vehicleyaw moment instruction calculator using the lateral jerk of the vehicle.9. The processor according to claim 7, wherein the vehicle yaw momentinstruction value is generated such that turning of the vehicle ispromoted when lateral acceleration of the vehicle increases but restoreswhen the lateral acceleration of the vehicle decreases.
 10. Theprocessor according to claim 7, wherein the vehicle yaw momentinstruction value is generated such that turning of the vehicle ispromoted when steering angle of the vehicle increases but restores whenthe steering angle of the vehicle decreases.
 11. The processor accordingto claim 7, wherein the vehicle yaw moment instruction value isgenerated on the basis of lateral acceleration and the lateral jerk ofthe vehicle and a predetermined gain, the lateral acceleration and thelateral jerk being generated from steering angle and velocity of thevehicle.